[HN Gopher] It's a DE9, not a DB9 (but we know what you mean)
___________________________________________________________________
It's a DE9, not a DB9 (but we know what you mean)
Author : jgrahamc
Score : 301 points
Date : 2025-07-25 13:35 UTC (9 hours ago)
(HTM) web link (news.sparkfun.com)
(TXT) w3m dump (news.sparkfun.com)
| dec0dedab0de wrote:
| I always just called it a serial port, because I could never
| remember DB9 to begin with. I really hope I remember this so I
| can impress some nerds in the future with how pedantic I can be.
| (I don't know how to write that last sentence without it sounding
| sarcastic, but I really meant it.)
| cestith wrote:
| Some other pedant might come along if you keep just calling it
| a serial port. They might mention that it's specifically
| RS-232, and that DB-25 is also used for that. They might also
| mention that "serial port" could include ports for RS-422 and
| RS-485. They might even mention SIO and USB.
| dragontamer wrote:
| Aren't Cisco switches (and a large number of other switches)
| loaded with Serial Port / RS232 over RJ45?
|
| DB9 or DE9 isn't even the end of it. There are lots of ways
| to run a serial line.
| Findecanor wrote:
| Are you sure those weren't using RS-232 over TCP/IP over
| Ethernet?
|
| That is quite common in the pro audio/video installation
| world, where RS-232 is common but needs extenders for
| longer distances.
|
| Within A/V, the norm for local RS-232 lines is actually not
| DE9 but 3-pin terminal blocks! (RX/TX/GND) I've seen those
| even on Cisco video codecs, priced $10'000+.
| dragontamer wrote:
| I'm talking about this thing
|
| https://www.amazon.com/Console-Female-Serial-Ethernet-
| Rollov...
| sokoloff wrote:
| I've got a bunch of Cisco switches with RJ45 connectors
| for the serial console ports.
|
| Here's the cable they use: https://www.bhphotovideo.com/c
| /product/1263972-REG/comprehen...
| numpad0 wrote:
| No, most Cisco devices has an RJ45 shaped RS232C port
| that needs a special cable to do anything with. It's
| proprietary, but there's one in every networking guy's
| backpacks so the situation is only as bad as Lightning
| cable for iPhone. Most(but not all!!) networking gears
| that compete with Cisco uses the same cable as well.
| mikestew wrote:
| _It 's proprietary..._
|
| Eh, depends on "proprietary", I guess. In the PLC world,
| using an RJ45 for a variety of serial uses is not
| uncommon. I've never touched a Cisco router in my life,
| but I've got a few things like these laying around:
|
| https://www.networktechinc.com/serial-rj45-adapters.html
| alnwlsn wrote:
| Null modem, crossover, DTE, DCE, straight-through, full
| handshaking, no handshaking, RS-232 or TTL levels. Plus
| CAN, RS-485, RS-422, CGA video, RGB video, and any number
| of industrial things use or can use the same DE9 connector
| (including sometimes for power).
| cestith wrote:
| I haven't touched Cisco gear in years, but that at least
| was true for a long time.
| icedchai wrote:
| DEC equipment had something similar. A 6 pin "MMJ"
| connector. It almost looks like RJ45 except the clip was
| off center.
|
| I also remember some 90's terminal servers that had
| enormous "octopus" cables. There was a single connector on
| the box that broke out to 8 to 16-ish DB25 serial ports.
| kps wrote:
| Some DEC equipment in the QBUS era also used DE9 serial
| ports, with a different pinout than IBM's.
| bwann wrote:
| and V.35 and X.21!
| raverbashing wrote:
| The thing I don't get about this is why did people think it
| was a good idea to have a serial connection over DB-25? You
| honestly need only 3 wires. Not 25
|
| For a Parallel port, sure 25 wires is right there. But not
| for a serial port
| kps wrote:
| CTS, DCD, DSR, DTR, GND, PG, RI, RTR, RTS, RxD, TxD
| (alphabetically) makes around 11, I think.
| II2II wrote:
| If I recall correctly, the DB-25 RS-232 cables also
| facilitated two serial connections.
| kps wrote:
| You do. (I've never seen that used, though.)
| chillingeffect wrote:
| Plus the differential versions of most of those signals
| for long distance doubles the number of pins. And they
| have optional synchronous clocks. I did some WAN work for
| 3Com back in the day... :)
| gchadwick wrote:
| I do wonder why they decided to have have separate shell size and
| pin designations given there appears to be a 1:1 correlation
| between shell sizes and pins (i.e. the 'B' shell is always 25
| pins, the 'E' shell is always 9 pins). Perhaps there was plan to
| have fewer pins in the same shell at some point?
| elsjaako wrote:
| DE15 and DA15 both exist and are pretty commonly used, I'm not
| aware of any other conflicts in normal versions.
|
| However, you can get weird Dsub connectors with things like
| COAX in there, so having the shell sizes have names can be
| useful.
| dfox wrote:
| Coax and high-current/voltage pins are not that weird. You
| can also get truly weird semi-proprietary pins like fiber
| optics or even pneumatics/fluidics.
| jones89176 wrote:
| it's not always 9 pins. you can get pretty creative regarding
| the number and type of pins (high current, coax) you can fit in
| that shell:
|
| DE with 2 High current contacts:
|
| https://de.wikipedia.org/wiki/D-Sub#/media/Datei:D-Sub_conne...
|
| DE with 15 contacts ("VGA"):
|
| https://de.wikipedia.org/wiki/D-Sub#/media/Datei:D-SUB_DE-9-...
| Am4TIfIsER0ppos wrote:
| https://en.wikipedia.org/wiki/File:D-Sub_connectors_size_DE_.
| ..
|
| https://en.wikipedia.org/wiki/File:D-SUB_DE-9-F_BLUE_VGA_IMG.
| ..
| geraldcombs wrote:
| There's also 13-W3: DB shell, 13 pins, 3 of them coax:
| https://en.wikipedia.org/wiki/DB13W3. They were used for
| high-end workstation video back in the day.
| donaldihunter wrote:
| I came here to share this cursed connector. I remember it
| well from Sun workstations
| bunnie wrote:
| VGA connectors used the same shell as the DE-9 but had three
| rows for a total of 15 pins.
| gchadwick wrote:
| An excellent example I really should have been able to think
| of myself!
| gjsman-1000 wrote:
| And for reasons I don't fully understand, somewhat
| unrelated - if you look around almost any small business in
| my area, it's almost always VGA, rarely DVI, almost never
| HDMI or DisplayPort.
|
| My theory is just that the cables came in the box and are
| screw-on when more modern connectors are friction fit, and
| the IT departments don't want the hassle of "they just got
| pulled out." Which should have been predictable - but I can
| literally see 12th gen Intel, paired with 1080p display,
| over VGA fairly regularly.
| dlcarrier wrote:
| DisplayPort has latching connectors, but they're easily
| broken when pulled out without unlatching.
| TheJoeMan wrote:
| For some reason DisplayPort monitors are more rare, and
| even when you get one like the MSI Pro MP241, it comes
| with an HDMI cable in the box!
| creaturemachine wrote:
| It's 100% because the VGA cable came in the box. Nothing
| about cables pulling because my lazy counterparts would
| not even screw in the DE15 cables half the time.
|
| Source: Too many years experience in the desktop support
| trenches.
| dec0dedab0de wrote:
| I vaguely remember there being some proprietary connectors that
| were the same as the standard with a single pin missing.
| dfox wrote:
| IBM did that pretty often. And well, the original VGA
| connector had pin 9 missing and used as a key.
| sjsdaiuasgdia wrote:
| IMO, the issue is less that there is a shell designation and
| more that the shell designation is hard to interpret.
|
| A single letter doesn't have a lot of meaning on its own, and
| the A-E order is not consistent with the E shell being smaller
| than all the others.
|
| By making it fully adjacent to the 'D', it makes the letter
| sound like it's part of the standard's name, like the 'RJ' in
| 'RJ45'.
|
| It would have been better to focus on pin count and row count,
| as those along with standard pin spacing drive the shell size.
|
| D-2R-15 for a two row 15 pin connector equivalent to DA-15,
| D-3R-15 for a 3 row 15 pin equivalent to DE-15 / VGA.
|
| Could trim out the 'R' and go with "D2-15" for 2 row and
| "D3-15" for 3 row, if brevity is preferred.
| cestith wrote:
| Confusingly enough, I've actually seen real, properly named
| DB-9 connectors. They were a cheaper version of a DB-25 to DE-9
| converter. Instead of combining the extra pins properly, they
| just had a DE-9 on one end connected to only 9 pins on the DB
| end. They sometimes occasionally even worked properly at low
| enough line rates.
| tiahura wrote:
| _The correct technical designation for a D-sub connector with
| nine pins is DE9._
|
| It's early and eyes are still a little blurry, but I'm not seeing
| a cite?
|
| Wikipedia fleshes it out a bit:
|
| _The D-sub series of connectors was introduced by Cannon in
| 1952.[3] Cannon 's part-numbering system uses D as the prefix for
| the whole series, followed by one of A, B, C, D, or E denoting
| the shell size, followed by the number of pins or sockets_
|
| No links to a primary source, but seems plausible.
| someothherguyy wrote:
| https://www.ittcannon.com/d-sub
|
| https://ittcannon.canto.com/direct/document/h10hf84e3l4n77ck...
| cwillu wrote:
| DB is easier to say, and everyone knows what I mean, so I will
| continue to say DB9.
|
| Standards that ignore human frailties will be corrupted by
| humans, and that's a good thing.
| elsjaako wrote:
| It's completely clear what you mean, so DB9 is fine. In most
| contexts calling it a DE9 will be more confusing.
|
| If you ever find yourself wanting to order the connectors or
| backshells, it might be useful to know it's actually DE-9.
|
| DB15 is the only one I have issues with. The company I work
| with has one container with "DB15" connectors (DA-15), and one
| with "DB15HD" (DE-15)
| 1970-01-01 wrote:
| My VGA (DE-15) and keyboard and mouse (Mini DIN #6) ports
| disagree. The printer port (DB-25) could not be reached for
| comment, as it is still set for uni-directional.
| dlcarrier wrote:
| Also, it's 8P8C, not RJ45, and sometimes it's more important to
| use the term from a standard body, but usually it's more
| important to use the term everyone knows. When documenting, I
| recommend saying something like this: J3 is an
| 8P8C jack (commonly RJ45) for IEEE P802.3bz 2.5GBASE-T
| communications, backward compatible with Gigabit and Fast
| Ethernet
| bobmcnamara wrote:
| Most 8P8C other connectors are incompatible with RJ45.
|
| Why wouldn't you say RJ45?
| bigbuppo wrote:
| RJ45 is a specific AT&T USOC order code to slap a normal 8P8C
| jack on someone's wall to provide something like multi-line
| analog telephone service.
| Sammi wrote:
| I used to do phone support for a phone company / isp and I
| have no idea what you just wrote.
| SV_BubbleTime wrote:
| He said RJ45 is an AT&T part/reference number. Just like
| RJ11 which is your small phone plug that had 6pins, more
| rare.
| arghwhat wrote:
| Nit: RJ11 has two contacts.
|
| RJ11, RJ14 and RJ25 all used the same 6P housing though,
| making them 6P2C, 6P4C and 6P6C connectors, respectively.
|
| Things sold as RJ11 is often 6P4C, making for another
| error. The rule of thumb is that anything referred to as
| RJ-something is likely wrong.
| craftkiller wrote:
| To be fair, 5 out of the 6 phone support agents I talked
| to at Optimum (an ISP) did not know what IPv6 is, so
| saying you used to do phone support for an ISP isn't
| really saying much.
| gjvc wrote:
| you tell him!
| SAI_Peregrinus wrote:
| RJ45 is a connector with a key notch sticking out and a
| "programming" resistor joining two of the pins. It won't
| work for Ethernet at all, the plug side can't even fit in
| the 8P8C socket Ethernet uses. If you grind off the key
| it'll still not work, because of the embedded resistor.
| Also the pinout is totally wrong, so even if you didn't
| have the resistor it wouldn't work. None of the RJ
| connectors have the correct pinout for Ethernet.
| arghwhat wrote:
| RJ45 is a mechanically (slightly) different connector, but
| indeed all RJ specs were for phone lines, with RJ45 focused
| on several lines for high speed modem connections.
|
| The regular ethernet 8P8C connector was defined by both an
| ANSI and ISO spec, neither of which gave the connector an
| actual name as it covers modular connector designs. :/
| LukeShu wrote:
| RJ45 is a _keyed_ 8-position jack, not a normal 8-position
| jack. ( "Keyed" means that there's a notch in the side
| making it a different shape; you would not be able to fit
| an "Ethernet" connector into it.)
|
| Closer is RJ38X, which is a _series_ 8-position jack, not a
| normal 8-position jack. ( "Series" means that the jack
| shorts pint 1 to pin 4 and pin 5 to pin 8 when there's not
| a cable plugged in to it; you would be able to fit an
| "Ethernet" connector into it, but even so it's probably not
| what you want.)
|
| AFAICT (skimming 47 CFR part 68, and the historical AT&T
| documents that became 47 CFR part 68), there is no RJ-
| number for a normal 8-position jack.
| pests wrote:
| > you would not be able to fit an "Ethernet" connector
| into it
|
| Because of the size being different? Surely a keyed
| female plug will take a male connector with or without
| the key. Or did you mean you couldn't fit a RK45
| connector into a Ethernet plug because then the key would
| interfere?
| wsh wrote:
| _RJ45S_ and _RJ45M_ are ordering codes for so-called
| "registered jack" configurations for terminal connections to
| the U.S. telephone network. These codes were defined until
| 2000 in the FCC Rules (47 CFR SS 68.502(e)) and later in the
| TIA /EIA-IS-968 standard, and they refer to single and
| multiple arrangements of two wires and a programming resistor
| on a miniature eight-position keyed jack.
|
| https://www.govinfo.gov/content/pkg/CFR-2000-title47-vol3/pd.
| ..
|
| Unfortunately, the "RJ45" part of these codes has become a
| metonym for the _unkeyed_ version of the miniature eight-
| position jack and plug, now widely used for Ethernet and
| other purposes, but strictly speaking, _RJ45_ refers to a
| different connector with totally incompatible wiring.
| LukeShu wrote:
| Specifically, what is colloquially an "RJ45" or "Ethernet"
| connector is an 8P8C "Bell System Miniature Plug/Jack"
| (AT&T's original name; it is a smaller version of the older
| Bell System connectors) / "miniature plug/jack" (FCC
| genericization of the name by removing "Bell System", even
| though the word "miniature" is no longer meaningful without
| context) / "modular jack" (ANSI/IEC genericization). That is
| what is meant when just "8P8C" is said.
|
| Pedantically speaking, RJ45 (as first defined by AT&T
| internally[1], and later by the FCC's 47 CFR part 68) is not
| that. The RJ45 socket is a _keyed_ 8P8C modular jack, not a
| regular 8P8C modular jack. Here is a photo: https://commons.w
| ikimedia.org/wiki/File:RJ45_female_connecto...
|
| [1]: The "RJ45" designation was originally an AT&T "USOC"
| (Universal Service Order Code). In the '70s, the FCC told
| AT&T that they had to allow interoperability from other
| companies, so the FCC had to publish a bunch of
| specifications; the meaning of "RJ45" became publicly
| specified in Bell System Communications' Technical Reference
| PUB 47101 "Standard Plugs And Jacks" (1979, though I think
| there might be an older number/revision from the early '70s
| that I haven't been able to track down). That (in combination
| with a few other technical references, such as PUB 47102),
| later became part of the Code of Federal Regulations, as 47
| CFR part 68.
| pythonguython wrote:
| Well you definitely SHOULD say RJ45. We do a lot of
| networking at my job and if I asked for an 8P8C connector, I
| would get confused stares. Say Ethernet cable, Cat 6 cable
| (or whatever cat), or RJ45. Sometimes being correct isn't the
| right thing to do.
| dontdoxxme wrote:
| 2.5GBASE-T? But I do 10GBASE-T over one. Provided it has Cat 6A
| cable inside it and has been tested to IEC 60512-9-3 & IEC
| 60512-99-002. (See
| https://ieee802.org/3/bt/public/oct15/Draft%20of%20IEC%20605...
| for some fun photos of what happens when PoE is disconnected on
| a connector before IEC 60512-99-002...).
| timerol wrote:
| The combination of "When documenting" and referencing "J3"
| indicates that dlcarrier is referencing a limitation of a
| specific port on a product that they worked on, not a set of
| global limitations on any 8P8C connectors
| dlcarrier wrote:
| I had assumed that the wires in the jack would rest along the
| bottoms of the blades in the plug, but I guess if it was
| never designed for high current applications, the contact
| area wouldn't be a consideration.
|
| It took a few tries to get it right, but it's amazing that
| PoE is even an option given how far it is outside of the
| scope of what the cables and connectors were designed for.
| I've heard of locations that use it for power, instead of 120
| V outlets, because it's cheaper and safer and most portable
| high-current appliances use batteries, while fixed high-
| current appliances use 240 V outlets.
|
| Hot plugging is always a challenge, especially with direct
| current, and negotiation prevents that from being a problem
| while making a connection, but I never considered that
| unplugging isn't negotiated first. I wonder if IEC has ever
| considered using a locking latch, like an EV charger.
|
| I have a PoE camera that I sometimes unplug to restart it,
| when it freezes up and I can't restart it from the web
| interface. I'll be sure to turn that port off first, before
| unplugging it.
| DHowett wrote:
| If you can turn the port off and then back on remotely,
| perhaps you can skip the unplugging part completely? I know
| that some managed PoE switches even offer a button to power
| cycle a port.
| bbarnett wrote:
| It's just the chip the NSA put in the cable, failing to
| initialize first try.
| formerly_proven wrote:
| You'll also enjoy annex H of https://usb.org/sites/default/fi
| les/USB%20Type-C%202.4%20Rel...
| OhMeadhbh wrote:
| Right. RJ45 was sort of like an 8P8C, but had a thing on the
| side so you actually couldn't plug a "real" RJ45 cable into a
| "normal" 8P8C slot.
| benlivengood wrote:
| And Molex power connectors are actually AMP Mate-n-Lok
| connectors.
|
| I didn't learn this until this year...
| dcrazy wrote:
| Which "Molex connector" are you referring to? The ATX spec
| specifically specifies Molex Mini-Fit part numbers, and
| claims this is for compatibility with PCIe: https://cdn.instr
| uctables.com/ORIG/FS8/5ILB/GU59Z1AT/FS85ILB...
|
| Is Mate-n-Lok perhaps a compatible product from a competitor?
| fredoralive wrote:
| It's the one the diagram of connectors calls "peripheral
| power connector" but the document doesn't seem to go into
| details for it. Basically the original PC drive power
| connector, so 5.25" drives, older hard discs, optical
| drives etc. use it, in the latter cases it's been replaced
| by the SATA power connector.
| numpad0 wrote:
| "Molex" usually refers to flat 4 pin AMP 1-480424-0 or
| Molex 8981-04P connectors(part number taken from random pdf
| on the Internet[1]). Confusing as it is... Actual Molex
| Mini-Fit are rarely colloquially referred to as Molex.
|
| 1: https://community.intel.com/cipcp26785/attachments/cipcp
| 2678...
| ssl-3 wrote:
| I've heard it argued that "Molex" means any extruded-pin
| connector.
|
| Like "Kleenex" means any facial tissue that is meant to
| be sneezed on.
|
| (Both uses are wrong, but both also tend to promote
| efficient communication.)
| SAI_Peregrinus wrote:
| And "JST" is used for any small white plastic connector
| with one side open showing the pins. "DuPont" means
| "Amphenol Mini-PV" or "Harwin M-20" or any other Mini-PV
| clone.
| 0_____0 wrote:
| I work a lot with connectors and I'm not really sure what
| you mean by extruded pin connectors. Typically the
| terminals are formed from sheet, unless you're using
| fancy 38999-style pins, which I believe are machined (and
| very expensive).
| dcrazy wrote:
| Ah, so it does appear that Mate-n-Lok is a name that
| AMP/TE uses for some Molex-compatible products. For
| example, TE's Micro Mate-n-Lok appears to be compatible
| with Molex's Micro-Fit.
| anonymousiam wrote:
| ...and Berg (0.1") connectors are now Dupont, even though
| Dupont doesn't make them anymore, and has had nothing to do
| with them since 1993. Everyone called them "Berg" in 1978
| when I was first exposed to them, even though Dupont had
| acquired the product line from Berg in 1972.
|
| https://www.reddit.com/r/electronics/comments/ioc6sf/i_final.
| ..
| 0_____0 wrote:
| A lot of connector series are are multi-sourced because big
| clients tend to require this. For example the 38999 series
| connectors used in military and aviation applications are
| made be TE, Amphenol, Souriau, ITT Cannon, Eaton...
|
| So it's really not uncommon to have manufacturers make
| something thing that a different company is known for. I
| think it's basically just luck that Molex got the credit for
| it
| aruametello wrote:
| _o/
|
| 100% guilty here, ouch.
|
| also never saw a 8P8C "keyed, real rj45" connector in person.
| mayli wrote:
| Yeah, I learned that rencently, engineers are dumb on naming
| things and remember the namings.
| os2warpman wrote:
| >What's in a Name? The D-Subminiature Standard
|
| "Standard" originally meant "an extended pole holding a flag or
| other marker" from the Latin "standardum" by way of French's
| "estandart".
|
| Now "standard" means "level of quality or attainment".
|
| Things change. Deal with it.
|
| It's DB9.
|
| Also, it's RJ45. Nobody cares what the real name is.
|
| In the entire history of humanity's ability to think and
| understand, exactly and precisely 0 people (ever) have been
| confused by either of those terms being used incorrectly.
| zettabomb wrote:
| Don't speak in absolutes, if you like being correct. In an
| engineering context, it's quite important that you know which
| one is which. I can and have ordered a B size shell with 9
| pins. This does not look particularly similar to whatever you
| are imagining - there are large power pins in the shell.
|
| Because we codified the nomenclature, the difference is
| important, and the standard "serial port" is a DE9 and nothing
| else. The word "standard" wasn't codified, but D-sub connectors
| were.
| os2warpman wrote:
| I do not think you are correct.
|
| D-subminiature connectors are codified by both IEC 60807-3
| and MIL-DTL-24308K.
|
| Neither IEC 60807-3 nor MIL-DTL-24308K "standardize" or
| "codify" D-subminiature connectors into DA/DB/DC/DE sizes.
|
| Is there an actual standard referencing DA/DB/DC/DD/DE? It
| wasn't linked in the article.
|
| I do not think there is, and I think that everyone claiming
| that DA/DB/DC/DD/DE is a "standard" is wrong.
|
| After all, we 100% DEFINITELY want to be "correct". Words
| like "standard" have meaning.
|
| It appears DA/DB/DC/DD/DE is just a trade practice started by
| Cannon. Maybe that's why the "standardized" and "codified"
| specifications refer to sizes 1 through 5 (or 6).
|
| If we want the opinion of the ultimate arbiters of
| standardization, both Digikey and Mouser adhere to "the
| standard" by organizing shell sizes into IEC 60807-3 and MIL-
| DTL-24308K-compliant numerical sizes with letters in
| parentheses to denote that the letters ARE NOT a standard.
|
| The most likely reason that DA-DE sizes are not in the
| standards is that DA-DE were once trademarks or otherwise
| proprietary designations created by Cannon. Indeed,
| practically the only consistent and quasi-official spec
| sheets that list the A-E sizes are published by ITT Cannon
| but even they reference the actual standards (e.g. "E Size 9
| (MIL-DTL-24308 Size 1)").
|
| I assert that DA-DE are proprietary designations created by
| Cannon (now ITT Cannon) and calling them a "standard" is
| incorrect, IN AN ENGINEERING CONTEXT.
|
| In support of my position I have referenced both IEC 60807-3
| and MIL-DTL-24308K and provided real-world examples from
| domain experts. I have also found pdfs for DIN 41652, CECC
| 75301-802 and referenced spec and marketing materials for
| Amphenol, Assmann, and Farnell/Newark and the only instances
| of a "standard" is when they list A-E sizes as an
| afterthought to aid people who are not following the actual
| standard to source standards-compliant parts (or ITT Cannon).
|
| What is there, besides blog posts, to show that I am not
| correct?
|
| edit: As a certified, triple-audited, ISO 9001-compliant
| weirdo, I am going to write up a nonconformity report,
| digitally sign it, print it out, manually sign it, then stamp
| it, then initial the stamp, then get it co-signed, stamped,
| and initialed, then scan it, then upload it into BMS, then
| print it out again, write the document control number on it,
| stamp and initial next to the document control number, have a
| second engineer stamp and initial it, and then hand it
| DIRECTLY to Quality if anyone ever refers to D-Sub connectors
| using non-standardized nomenclature ever again.
|
| This is serious business and we are serious engineers here.
| shermantanktop wrote:
| This is like King Canute and the tide. Technical pedantry is
| often interesting, as this is, and can lead to deeper
| understanding, though this doesn't.
|
| But language is for communication, and the most correct language
| is that which communicates best.
|
| A conversation burdened with "well actually" tangents about one
| participant's personal passion gets pretty tiresome.
| dogleash wrote:
| Being on the sharp edge of professional "do you want what
| you're asking for, or what I assume you want?"
| misunderstandings, you learn that it breaks in both directions
| often enough that sometimes not being pedantic up front isn't
| an option.
|
| I don't think shittalking "well actually" conversations in the
| context of an _equipment vendor_ making a cutely-titled article
| that is very sympathetic to the inexact language around
| _designators for products_ they offer is the play.
| tetha wrote:
| This is why I've learned to present people with the concrete
| consequences and results of their service request. Especially
| if I get the feeling that someone does not comprehend what
| they are asking for.
|
| "Your service request will result in X hours of downtime, as
| well as ireversible data loss between T1 and T2, and a reset
| of your system back to the state it was in at T1. All changes
| and interactions after T1 will be lost. Is this what you
| expect and want?"
|
| Beyond a certain amount of service disruption or monetary
| investment, asking twice and making sure is prudent, not
| pedantic.
| xp84 wrote:
| In this case, is it that helpful? Since only a lunatic would
| want a true DB9 and no one's ever made a giant connector with
| 9 pins, I fail to see the importance.
| aleph_minus_one wrote:
| > But language is for communication, and the most correct
| language is that which communicates best.
|
| This seems to be biased in US-American culture. In Germany,
| people are in my observation much more prone to analyze words
| and sentences (often by their origins), and many people
| wouldn't accept a "wrong" way to express things to be correct.
|
| Just to give one example (which also works in English): "[die]
| Alternative" (the alternative): this word comes from Latin
| "alter, altera, alterum" ( _the_ other). This means, that there
| exists only _one_ other. So educated people love to point out
| that talking of multiple "Alternativen" [alternatives] is
| wrong; by the word origin there can only exist _one_
| alternative ( _the_ other one). If more than one
| "alternatives" exist, so, to be precise, you likely want to use
| a different word.
| UncleSlacky wrote:
| "(The/an) alternate" is probably the _ahem_ _alternative_
| term you 're looking for...
| aleph_minus_one wrote:
| I am not a native English speaker, so I honestly was not
| aware of this English word.
|
| Addendum: nevertheless: "alternate" is also derived fron
| "alter, altera, alterum" ( _the_ other one), so my point
| above still holds.
| horsawlarway wrote:
| I think this implies a meaning of "the" that doesn't actually
| exist in modern english.
|
| "The" often refers to a group or category.
|
| "The other" is actually a phrase I would take to be
| incredibly _inclusive_ in meaning if not followed by another
| specifier (it means "the category of everything that is not
| us").
|
| "The alternative" is similarly a category structure. It's a
| singular category, made of many possible members, or
| alternatives.
|
| You may still only pick a single alternate for each case, but
| that does not mean that a category of multiple possible
| alternative choices does not exist.
|
| ---
|
| All that said, sparkfun is messing up by labeling this DE9.
| Spoken as someone who's done quite a bit of serial
| communication work. The defacto industry term is DB9, whether
| they like it or not, and most searching/purchasing will be
| done using that term. This is a "technically correct" fun
| article, with a name that would immediately mean I don't ever
| find this product (and would not purchase this product)
| unless they highlight that this is a DB9 breakout board with
| a bad name.
|
| Simple test? Amazon has more than 4000 results for "db9
| cable" and only ~110 results for "de9" cable. Even specialty
| sites like McMaster, which are usually pretty particular with
| their terms are happily calling this a db9 connector:
| https://www.mcmaster.com/products/connectors/computer-
| connec...
| aleph_minus_one wrote:
| > I think this implies a meaning of "the" that doesn't
| actually exist in modern english.
|
| > "The" often refers to a group or category.
|
| But this does not hold for the meaning of Latin "alter,
| altera, alterum" (the other _one_ ), from which the German
| and English word "Alternative"/"alternative" is derived.
| shermantanktop wrote:
| I think you're proving my point. If the people I am talking
| to and the language I am using both demand precision in word
| choice, then I would be foolish to use the wrong term and
| then say "well, you should have known what I meant."
|
| But that is a communication context, and there are other
| contexts where implications and assumed meanings are
| expected, and spelling everything out would be considered
| pompous, self-important, and ridiculous.
|
| Perhaps not in Germany? But certainly elsewhere (but i
| believe that in German the pronoun "sie" can require assumed
| context to understand).
| csours wrote:
| It depends on context. If you're working from a document that
| is otherwise correct, and you come across a mistake like this,
| it's worth checking.
|
| In casual language, sure, whatever.
| Findecanor wrote:
| There also existed non-standard D-subminiature connectors that
| didn't fit within that nomenclature.
|
| For instance, the Amiga used _23_ -pin connectors to connect
| displays and disk drives. They had the same pin spacing as DB25
| but were slightly smaller.
| jgrahamc wrote:
| And there's the infamous DB-19:
| https://www.bigmessowires.com/2025/06/30/bulk-lots-of-db-19s...
| 9rx wrote:
| Wouldn't it fit into the nomenclature with another shell type?
| DF, perhaps?
|
| It is not like there is any real sensibility to the naming
| anyway. Of the common types, DA, DB, and DC seem to follow a
| pattern, but DD and DE then go completely off the rails.
| 9rx wrote:
| _> To be blunt, the term "DB9" is plainly inaccurate because it
| pairs the 25-pin "B" shell with a 9-pin count, a physical
| contradiction._
|
| Why couldn't a DB shell house a 9 pin connector? I don't see the
| physical contradiction (even if nobody actually manufactures such
| a thing).
| relaxing wrote:
| Sure you could do it. You could even put 25 pins in 9 pin
| housing if you made the pitch smaller.
|
| They just don't exist, and hopefully never will.
| 9rx wrote:
| What's the physical contradiction, then? I don't get it.
| aleph_minus_one wrote:
| The physical contradiction is that the standard requires a
| particular pitch of the pins, and a specific distance of
| the pins from the shell.
| 9rx wrote:
| What's the point of "9", then? And how do you explain
| DE15 (popularized by VGA)?
| khedoros1 wrote:
| > What's the point of "9", then?
|
| Originally? Because that was the naming convention that
| Cannon designated. Later, because the shell size wasn't
| sufficient to determine the number of pins.
|
| > And how do you explain DE15 (popularized by VGA)?
|
| Cannon's D-series connectors started with 2 rows, at the
| "normal density" of 326/3000 of an inch between pins.
| They later expanded the range of connectors with "high
| density" and "double density" connectors that put more
| pins at greater densities into the original shell sizes.
| DE15 is in the "high density" range.
| jrockway wrote:
| In a world with 3D printers, everything can potentially
| exist.
| relaxing wrote:
| Man-made horrors etc.
| Perz1val wrote:
| So if I put USB type C into a DB shell should I call it a
| DB-USB-C?
| SAI_Peregrinus wrote:
| Yes, of course. You should be able to fit more than one
| in there, with a hub in the connector housing!
| reaperducer wrote:
| _Sure you could do it. You could even put 25 pins in 9 pin
| housing if you made the pitch smaller.
|
| They just don't exist, and hopefully never will._
|
| Maybe not as a standard, but I've seen a several companies
| stuff a crazy number of pins into a DE9 shell. I think one of
| them was my old GRiD Compass.
|
| Beast of a machine. Heavy as hell, magnesium case, bubble
| memory, a screen that caused all televisions it was pointed
| at to lose their signal, and a sticker on the bottom saying
| it was illegal to use it in a whole list of countries,
| including Israel.
| leptons wrote:
| Seems like it has 19 pins in a DE9 shell. That's a lot. VGA
| connectors were also in a DE9 shell, but had 15 pins.
|
| The funny thing about the GRiD DE9 connector is that it's
| labeled "Serial", but every DE9 serial port connector I've
| ever seen is 9-pin. I have to wonder what else they are
| cramming into that 20-pin DE9 "serial" port.
|
| http://raster-burn.net/wordpress/wp-
| content/gallery/grid-113...
| leptons wrote:
| VGA connectors were a DE-9 shell with 15 pins in them, and
| were used widely for many years to connect monitors to
| computers. There are other connectors that crammed 19 pins
| into a DE-9 shell. 25 might be a bit too much, but 19 is
| pretty close.
| somat wrote:
| Heh flashback, I had an ati all in wonder, which was a video
| card with built in video capture. Now this involves a lot of
| ports so the model I had used a port breakout dongle for the
| video capture stuff, and some engineer had the bright idea to
| run all these pins through a mini-din connector. Think a ps/2
| connector with about 10 pins crammed into it. Now ps/2
| connectors are sort of stupid in the first place. why a round
| connector that is keyed to only go in one way? But this 10
| pin variant was a nightmare to insert and by about the third
| time I made a firm resolution to never unplug it again if I
| could help it.
|
| Footnote: keyed round connectors are not actually that bad,
| super strong, easy to seal and you can fit a large nut or
| bayonet clamp to them to make them extremely secure. However,
| this depends on having a well placed shell/key and mini-din
| doesn't, it is a bad connector. Not enough shell and key for
| solid locating so the pins tend to ride on the face while you
| try and orient it.
|
| I think this was the one I had.
|
| https://www.techpowerup.com/gpu-specs/all-in-
| wonder-9600.c86...
| bigbuppo wrote:
| It can, but nobody would do that as it would be cheaper to use
| a DB-25 connector and not use all the pins. If they went for
| the cursed true DB-9 they would need to meet the minimum order
| quantity for a special order, pay for the manufacturer's
| tooling, and any required certifications. If you needed the
| spacing between pins for some reason you would probably just
| specify the use of crimp-and-insert.
|
| That being said, the DE-0 is real, but it can't hurt you.
| alex7o wrote:
| Searching google for DE-0 didn't bring any results but now I
| am curious to see it.
| axoltl wrote:
| https://uk.rs-online.com/web/p/d-sub-connectors/0481049
| https://uk.rs-online.com/web/p/d-sub-connectors/2748593
| arghwhat wrote:
| > That being said, the DE-0 is real, but it can't hurt you.
|
| That depends on several factors, like its current velocity.
| crtified wrote:
| While your statement is perfectly accurate, I just wanted
| to blithely add that it's not the velocity that hurts you,
| it's the _change_ in velocity :))
| jameshart wrote:
| You can remove pins from D-sub connectors. There are
| dedicated tools made for doing so.
| mmastrac wrote:
| In a pinch, a pair of pliers works too.
| arjvik wrote:
| Doesn't VGA use DE-15?
| ianburrell wrote:
| Edit: I was wrong, it is DE-15 connector. They squeeze 15
| smaller pins into 9 pin housing.
| mbreese wrote:
| I've seen (many... many years ago) a DB housing with 9
| connectors but with the spacing of 25 pins. Would this then be
| a DB25C9P?
|
| In retrospect, I think this may have been an adapter from DE9
| to DB25, but it would have been a quick way to save a few
| pennies when only 9 pins were used for serial communication.
| bombcar wrote:
| I've seen this also - I am unsure if it was a cost cutting
| measure or something else, but I've seen more than one
| connector with many missing pins.
| II2II wrote:
| The cables I saw were handmade. You can get connectors
| which are just the shield and an insulator with holes in
| the place of the pins. You crimp the pins onto the wires,
| then slide the pins into the insulator. You may have saved
| a few cents by not inserting the unconnected pins, but the
| reality is that most people left them out because there was
| no point in going to the trouble of putting them in.
| numpad0 wrote:
| Another possibility is Sun or SGI 13W3 display connector.
| They were DB25 shaped connectors with 10 regular pins and 3
| giant pins for video signals.
| mbreese wrote:
| True. However, mine were for connecting to modems, so they
| were definitely only 9 pin serial cables. I didn't have the
| pleasure of seeing the 13W3 connectors until I was in grad
| school, and I still think they look weird. It didn't occur
| to me until today that they were the exact same size/shape
| as the DB connectors. They were so different that the
| thought never occurred to me!
| II2II wrote:
| How would you even count those 3 giant pins? If I recall
| correctly, they were for coax cables that ran within the
| main cable. So each of those pins would have a contact for
| the shield and the conductor.
| kps wrote:
| It was pretty common for RS232 (-ish) DB25 connectors not to
| populate unused pins.
| javcasas wrote:
| "DB" already means 25 pins, so well, it's quite hard to both
| have 25 and 9 pins at the same time.
|
| That is still pedantically different from a DB-25 of which we
| ripped out pins until it had only nine. The result would be "a
| DB-9" in big quotes, as it would't be "a", but more like "3/4
| of a DB-25".
| SAI_Peregrinus wrote:
| DB housing can fit 25 pins in 2 rows. But it can also fit 9
| really honkin big pins in 1 row, with a custom mold & pins.
| 3x groups of 3x12-gauge pins for 60A 3-phase delta power
| connector in a DB sized shell would probably work for a while
| before you burn your house down.
| javcasas wrote:
| You mean this?
|
| https://adamconn.com/product/8w8-connector
|
| It's 8 pins, so, sorry, I'm not accepting it as DB9-of-
| doom. Maybe DB-8-of-doom.
| jcoby wrote:
| > "DB" already means 25 pins, so well, it's quite hard to
| both have 25 and 9 pins at the same time.
|
| No, it doesn't. All of the D-Subs are readily available in
| high density versions: DA-15 | DA-26
| DB-25 | DB-44 DC-37 | DC-62 DD-50 | DD-78
| DE-9 | DE-15
|
| The high density versions are commonly used in aerospace
| applications. Garmin is pretty fond of them.
|
| There are also double density connectors putting 52 pins in a
| DB housing and whopping 100 connectors in the DD housing.
| rchard2scout wrote:
| Also DE-15 is the standard connector used for VGA.
| jameshart wrote:
| I have a vague memory of a computer (probably in the 16 bit
| era?) saving money on providing two joystick ports by using a
| DB25 housing with the middle pins removed, leaving two 9 pin
| clusters at the ends, into which two DE9 joysticks could be
| plugged. The case plastic covered over the middle of the
| connector.
| spiritplumber wrote:
| It was an accessory to let you use Amiga joysticks on the PC,
| from the mid 90s. I had one.
| jameshart wrote:
| Could well have been, though I'm still picturing a computer
| in my mind. Wasn't the SAM Coupe, but that's the sort of
| thing I'm recalling.
|
| But: it was probably quite common on joystick interfaces,
| now you mention it. Thinking along those lines and
| searching for 'twin joystick adapter' let me actually find
| an example: https://www.ebay.com/itm/276075015721
|
| Worth noting that in the image that shows two joysticks
| plugged in they really don't look like they fit all that
| well...
| alnwlsn wrote:
| There's a lot of things like this, especially when the connector
| is commonly used for just one thing. One is "composite video"
| which at one point or another I have heard items on this list
| used interchangeably (though not always at the same time):
|
| composite video - RS-170 - monochrome video - EIA-170 - NTSC -
| black and white video - CVBS - B&W video - RS-170A - analog video
| - PAL - yellow RCA plug - just plain "video"
|
| These don't even all refer to the same thing, and some are
| definitely more correct than others, but all are used even by
| technical people.
|
| Here's another one: "Amphenol connector", "Cannon connector" or
| "Molex connector". It's the same as saying "Ford car".
| deathanatos wrote:
| The 1.44 MB diskette is my canonical "dear God what
| happened"-named thing.
|
| The traditional diskette is 1440 KiB. I.e., base-2, today named
| "kibibyte" though in that day that word didn't exist yet & it
| was just a kilobyte and the base 2 inferred from context.
| Clearly, someone didn't infer, and moved the decimal, so that
| 1.44 "MB" is 1.44 * 1000 * 1024 bytes. The actual capacity is
| thus either 1.41 MiB or 1.47 MB.
| hinkley wrote:
| Hard drives continued to make that mistake, and once you got
| to GB size they were overselling the disk space by an
| appreciable amount.
| alanfranz wrote:
| hard drives intentionally use giga and tera rather than
| gibi and tebi. They're right; it's the memory sticks that
| are usually wrong :-)
| chuckadams wrote:
| Nobody says "gibibyte" out loud without giggling or
| getting giggled at. I think we should start saying
| "gigglebyte".
| hinkley wrote:
| Know that several of your coworkers are laughing at you
| in their minds every time you utter such foolishness.
| bombela wrote:
| I have had to debug enough fires because of stupid unit
| confusion that I now make the point of being extremely
| pedantic with the use of the right unit.
| genewitch wrote:
| jigglybits works too in the correct company
|
| also cal state irvine had a compsci prof who said "jigga-
| byte"
| hinkley wrote:
| One point twenty one jiggabytes??? Great Scott!
| edoceo wrote:
| I've been calling them Kibbles, Marbles, Gerbils and
| Tribbles
| hinkley wrote:
| Pebble scale computing is all the rage right now.
| jimmaswell wrote:
| IMO it's the ISP's who are intentionally misleading
| people. Average Joe _might_ have some inkling of how big
| a gigabyte is these days, but nobody except a network
| engineer cares what a gigabit is. I can 't imagine how
| many people buy gigabit fiber expecting a gigabyte. It
| would sound much less impressive if it were marketed as
| 125MB/s like it should be. They should at least be
| required to show both, not make people convert units if
| they want to find out how fast their advertised internet
| is supposed to download their 50GB game.
| hnuser123456 wrote:
| You could also blame Windows. Linux counts storage bytes
| in base 10. But still counts RAM in base 2.
| bigbuppo wrote:
| I thought they tossed the fool that tried to make mebibyte a
| thing off a bridge and we tried to forget about that.
| yjftsjthsd-h wrote:
| Perhaps the _formatted_ capacity, or the safe capacity, but I
| can specifically recall being able to format those same
| floppies up to... I forget, maybe ~2MB? Something like that.
| krs_ wrote:
| Same with older floppy disk formats. Using FAT16 (or FAT12
| on some systems) you can often format DD 3.5" disks to 830K
| instead of the usual 720K. On the Amiga the same disks are
| usually 880K.
| deathanatos wrote:
| Yes, the typical formatted capacity. The word "traditional"
| was the brevity which was attempting to sum that up.
|
| There were also other, weirder setups where you could get
| various other capacities. It was a wild time.
| bigstrat2003 wrote:
| > today named "kibibyte" though in that day that word didn't
| exist yet & it was just a kilobyte and the base 2 inferred
| from context
|
| That is still what most people do. Only _very_ pendantic
| individuals insist on using KiB, etc. Normal people are just
| fine inferring from context whether base-2 or base-10 is
| meant.
| wsh wrote:
| You forgot SMPTE 170M, which is probably the definitive
| standard at this point:
|
| https://pub.smpte.org/doc/st170/20041130-pub/st0170-2004_sta...
| bigfishrunning wrote:
| My favorite example of this is using "aux cable" to refer to an
| audio cable with a 3 or 4 pin 3.5mm connector on the end
| (because car stereos would have a 3.5mm jack labeled "Aux" for
| "Auxiliary input")
|
| I usually call those "headphone cables" just to be contrary.
| brudgers wrote:
| _You have been misusing the D-sub connector terminology_
|
| No I haven't and the same is true for approximately everyone
| else.
|
| Because we have not been using D-sub connector terminology at
| all. We have been talking about the things that come with (and
| without) DB9 connectors. We have been (mostly) playing --- as the
| witty Wittgenstein would say -- a different language game.
|
| That's why you know what I mean. So bring me a slab.
| andix wrote:
| If you keep calling it DB9 everybody knows what you're talking
| about. They don't think you're weird and they also don't waste
| time talking about terminology.
| OhMeadhbh wrote:
| Words mean things. Especially in engineering disciplines.
|
| It's perfectly fine for a product manager to say "DB9", but the
| guy who has to order the part from a supplier will probably
| want to use the correct terminology. If there's a mistake, it's
| the supplier's fault.
| orphea wrote:
| > Words mean things.
|
| I struggle with someone I work with because of this :( They
| might as well call a DB9/DE9 a USB connector and expect
| everyone to understand them. They're both connectors after
| all, right?
| 9rx wrote:
| _> If you keep calling it DB9 everybody knows what you 're
| talking about._
|
| But might question what your wiring has to do with a 2000s-era
| Aston Martin.
| andix wrote:
| AI image generation can finally express what I picture when
| hearing Aston Martin DB9:
| https://chatgpt.com/s/m_6883b37e1fc881919e3af8f862aa7900
| yonatan8070 wrote:
| "DE10 isn't real, it can't hurt you"
| OhMeadhbh wrote:
| We used the DD-50 connectors in the telephony world and called
| them "DD-50 connectors." I always wondered why they were "DD-50"
| and the 9 and 25 pin connectors were "DB-9" and "DB-25". Now I
| know... we were just using the nomenclature wrong.
| Cyan488 wrote:
| Sparkfun should take it upon themselves to correct the centuries-
| old mix-up of "conventional current" next :)
| stn8188 wrote:
| I always thought this was really interesting. The Coast Guard's
| Electrician's Mate training program taught electron-flow
| theory, so it was tough to switch my brain to hole-flow theory
| when I went to college. Technically the math is the same but
| man it threw me off with schematics.
| DecentShoes wrote:
| What's that?
| phendrenad2 wrote:
| Could the name "DB9" have come from 25-pin serial ports with only
| the minimum 9 pins populated? That would be a correct "DB9" and
| would also be valid electrically. I think I've even seen one of
| those in the wild before.
| codazoda wrote:
| Interestingly they have 25 to 9-pin adapters and the majority
| of DB25 devices I worked with were fine either way. So, the
| devices generally used 9 pins or less (or at least 9 or less
| pins were "important").
|
| There are, of course, devices that use more than that, but most
| things seemed to use less. Maybe that's part of the reason the
| 9-pin became more standard.
| nick__m wrote:
| Frequently only 3 pins are used in a DE-9.
| gowld wrote:
| So, the [ABCDE] in D?-N is redundant and useless, so it doesn't
| matter what letter you use. Humanity triumphed, eliminating
| useless redundancy.
| mauvehaus wrote:
| No, because a VGA port is a DE-15 and a DA-15 is used for, uh,
| something?
|
| ETA: Oh hey, just to make things confusing, Apple used DA-15
| for video on older Macs.
|
| https://en.m.wikipedia.org/wiki/D-subminiature
| fredoralive wrote:
| DA15 was used for amongst other things Mac video outputs in
| the beige era, PC joystick / MIDI ports and Ethernet AUI
| ports.
| encom wrote:
| Given that DB9 is so pervasive (and I admit this is new
| information to me), I thought AI training data might include the
| error but no, ChatGPT knows DB9 is wrong:
|
| https://chatgpt.com/share/6883b2ff-d26c-8002-bc4d-b184d7afd4...
| tycoon666 wrote:
| What's about the 19 and 23 pin variant
| krs_ wrote:
| Some discussion on the 19 pin variant from last year:
|
| https://news.ycombinator.com/item?id=40397593
| zettabomb wrote:
| D-sub has got to be one of the longest enduring connector
| standards I can think of, apart from wall outlets. They're from
| the 50s, originally for military use, and we're still speccing
| them in new space hardware today. Now they've got coax/twinax,
| high power, fiber, and even pneumatic "contacts" if you know
| where to look (and can afford it). I can't say that they'd be my
| first choice, personally, but it's quite remarkable to see how
| well they've fared over the better part of a century.
| paradox460 wrote:
| Phone jacks. Invented in the late 19th century. Still in use
| today.
| zettabomb wrote:
| I assume you're referring to the 1/4" jacks, not RJ series?
| EvanAnderson wrote:
| I assume you're talking about these, right?
|
| https://en.wikipedia.org/wiki/Phone_connector_(audio)
| bluGill wrote:
| XLR used (mostly) in audio is also from the 1950s.
|
| The biggest problem with these standards is they are used for
| everything and so you cannot be sure that if the cable fits it
| will work. If a USB cable fits it will almost always work - but
| if it doesn't it will be obvious to your average idiot way
| (that is you can plug a mouse into a power supply - but nobody
| expects it will work). USB-C somewhat violates that, but even
| still it mostly is a case if you can get the connectors to fit
| it works.
| zettabomb wrote:
| Didn't even think of that, yes of course XLR and for that
| matter, 1/4" TS/TRS connectors were originally for switching
| phones at AT&T, before automated switching. Incidentally, you
| can also blow up quite a bit of stuff with them, depending on
| whether they are at consumer "line level", pro audio "line
| level", or even speaker level. We're definitely too
| comfortable with "if it fits, it works" (or at least isn't
| harmful".
| jameshart wrote:
| There was a wild period in early transistor electronics
| where DC power adapters sometimes used 1/8" phone jacks -
| before the barrel-style DC plugs became common. Having 9V
| DC in a form that could be plugged into a microphone input
| always seemed like a pretty insane choice.
| genewitch wrote:
| i blew up my atari in the 1980s with one of those plugs.
| namibj wrote:
| I'd like to mention my USB-stick-shaped audio
| recorder/player who's headphone jack (only uses built-in
| mic in any case, though iirc the headphone button skips
| to the next file) functions as the computer and charging
| connector. The device was shipped with a cable (USB-A
| male) <> (TRRS 3.5mm aka 1/8") for this usage. It reports
| as mass storage.
| geoffpado wrote:
| Apple shipped a few iPods that were like this, too:
| https://en.wikipedia.org/wiki/IPod_Shuffle#2nd_generation
| spongeb00b wrote:
| Apple even used the 1/4" jack for the Lisa keyboard https
| ://archive.computerhistory.org/resources/access/physica..
| .
| jameshart wrote:
| DIN connectors also date from the 1950s, so do coax F
| connectors (the screw-coupled connectors for cable TV).
|
| RCA/phono jacks are from the 1930s - when record players and
| radios were first a thing.
|
| But headphone jacks - originally phone switchboard jacks -
| are way older, dating to the 1870s.
| adolph wrote:
| The 1878 one is fascinating:
|
| When the plug is inserted, the jack "breaks its normal
| connection." Like they didn't want to leave the audio
| output like a floating pin to reduce stray voltage?
|
| Scribner calls the switch "spring-jack" after "jack-knife"
| where the "jack" part of it comes from the name Jack and in
| the 1300s meant a mechanical device. So the "female"
| component of the connection was thereby given a "male"
| name. Charles E. Scribner filed a patent in
| 1878 to facilitate switchboard operation using his
| spring-jack switch. In it, a conductive lever pushed by a
| spring is normally connected to one contact. But when a
| cable with a conductive plug is inserted into a hole
| and makes contact with that lever, the lever pivots
| and breaks its normal connection. The receptacle was called
| a jack-knife because of its resemblance to a pocket clasp-
| knife. This is said to be the origin of calling the
| receptacle a jack. Scribner filed a patent in 1880
| which removes the lever and resembles the modern connector
| and made improvements to switchboard design in
| subsequent patents filed in 1882.
|
| https://en.wikipedia.org/wiki/Phone_connector_%28audio%29
| late 14c., jakke "a mechanical device," from the masc. name
| Jack. The proper name was used in Middle English for
| "any common fellow," and thereafter extended to
| various appliances which do the work of common servants
| (1570s).
|
| https://www.etymonline.com/word/Jack
| em3rgent0rdr wrote:
| I don't think it was about not wanting to leave the audio
| input floating. Rather the "normal connection" is that
| the telephone subscriber is connected directly to the
| switchboard operator's annunciator (a display panel) so
| that the subscriber can light up a bulb on the
| annunciator when that subscriber wishes to ask the
| operator to reroute that subscriber's connection to
| another subscriber (instead of to the switchboard
| operator). This is why the switch ought to act like a
| double-throw, not just a single-throw switch. I think
| something along those lines is the reason...
|
| > In a telephone-exchange system the wires of the several
| subscribers are run into a cen tral office, where, upon
| request, any wire may be connected with that of any other
| subscriber.
|
| > In Fig. 4 is shown the cut-out connected with
| subscriber's wire in and the relay and annunciator P and
| O, and also, with the operator's telephone J, by means of
| the plug A, which is provided with a metallic point, and
| conducting-cord d. The connections are formed as follows:
| The subscriber S, by throwing on his local battery, sends
| a current along the wire in through the relay P, which,
| closing, the annunciator number of S is indicated at O,
| and the current passes along the Wire H, and thence
| through the switch to the ground Wire G.
| jdietrich wrote:
| European TVs still use an antenna connector that was introduced
| in 1922.
|
| https://en.wikipedia.org/wiki/Belling-Lee_connector
| op00to wrote:
| Frankenstein's _monster_!
| rzzzt wrote:
| I was looking for this one. Three angles for a potential
| retort:
|
| a) Frankenstein is the real monster in the book
|
| b) The monster is Victor's son, so inherits the family name and
| thus is also (a) Frankenstein
|
| c) A modern adaptation gives the reader explicit permission to
| use "Frankenstein" as the name for the monster:
| https://xkcd.com/1589/
| op00to wrote:
| I prefer to calm them "Frankensteins", like:
|
| "Look out, there's a Frankenstein to push into that lake!"
|
| But can never resist the Frankenstein's monster pedantry, I
| find it hilarious.
| tekawade wrote:
| This is great. Maybe having total or stats/tools for comparison
| will be awesome plus.
|
| Set input and output and check cost.
| lttlrck wrote:
| The examples would illustrate the issue a little better if there
| were two pin counts with the same shell, eg DE9 and DE15 and
| maybe two shells with the same pin count (though I'm not aware of
| such an example).
|
| Without that it is barely worth the distinction.
| mixdup wrote:
| Yep, was going to comment on this aspect. If you can't have a
| DB-9 (which would be the large shell but with a bunch of
| missing pins) they should have just called the m DA-DE or
| D-(number of pins)
| lutusp wrote:
| This might not prevail in the world of tech, but in language
| studies, words mean what the majority of their users think they
| mean. Examples: * Decimated. How many of you
| know this means (or once meant) reduced by 1/10? *
| Literally. Often used to mean figuratively, to the degree that it
| can be relied on to mean nothing at all. * Reign, as in
| "reign him in". Clearly now an accepted misuse, reign once
| defined what a monarch does to a kingdom, not what a cowboy does
| to a horse (i.e. rein). * Fewer / less. Sadly
| interchangeable in modern writing, "fewer" was once reserved for
| enumerable things, while "less" referred to continuous measures.
| Less water, fewer liters of water. * Double precision. In
| computer science, defined in IEEE 754 as a floating-point data
| format with a 53-bit mantissa, therefore 15.95 decimal digits (53
| * log(2)/log(10)). Now the norm, the default, to the degree that
| people may forget what "double" refers to. Because of double's
| ubiquity, in the fullness of time I expect single precision will
| come to be known as ... wait for it ... half precision.
|
| Lexicographers are at pains to point out that words mean what
| people think they mean. I think they have a point.
| owenfi wrote:
| https://connectorbook.com/identification.html?N=&n=d_sub_con...
|
| See the online interactive adjuncts here:
| https://connectorbook.com
| pimlottc wrote:
| DB25 and DB9? Oh, you mean parallel port and serial port? :)
| fhars wrote:
| DB-25 is the standard RS-232 connector. DE9 is just the cheap
| alternative for cases where you don't need all control lines
| HarHarVeryFunny wrote:
| Doesn't a DB9 connector include all the DB25 RS-232
| handshaking lines, even if not all devices actually use them?
|
| I grew up in the 70s-80s with serial connectors and a drawer
| full of cables, DB25-DB9 adaptors, gender-benders, null
| modems, breakout boxes, etc, and the only (very common)
| source of incompatibility that I can recall was connecting
| devices where one side wanted hardware handshaking but the
| other didn't provide it, so having to make custom cables with
| handshaking tied hi/lo to fake it.
|
| Some devices used software XON/XOFF handshaking, so for
| example on a typical terminal, depending on what you were
| connected to, you could pause text being sent to the terminal
| with XOFF (Ctrl-Q), and resume with XON (Ctrl-S).
|
| I've got a softspot for serial communications - used be more
| a source of fun rather than frustration to dip into the draw
| of cables/etc and get two devices happily talking to each
| other.
| ac29 wrote:
| > Doesn't a DB9 connector include all the DB25 RS-232
| handshaking lines
|
| Handshaking yes, but not all potential RS232 signals, of
| which there are 11.
|
| I work with RS232 frequently and even CTS/RTS is rare to
| use. Never personally seen anything use DTR, DCD, DSR, or
| RI though I know they did see historical use.
| HocusLocus wrote:
| The real reason is that in the 1980s this illustration (
| https://cdn.sparkfun.com/assets/home_page_posts/1/4/2/9/8/DS... )
| was not shown to people. And an illustrator, probably who hadn't
| seen it either, is who got it wrong. I don't blame them. The
| existence of an arbitrary letter invariably joined with a useful
| and descriptive number is the fault here. And the illustrator
| could NOT show the whole thing anyway because it contained
| diagrams of products not sold. The perfect setup.
|
| That is all. Everything else is blah blah blah (about DB9, love
| all the examples of other goofy identifiers!)
|
| People strive for accuracy and remember things. I love people-in-
| general and they have an impressive track record. They improved
| on the standards committee.
| HarHarVeryFunny wrote:
| IMO this is a case where being correct causes confusion rather
| than clarity. Everyone calls this connector DB9, so calling it
| DE9 is going to make people wonder if it's really a DB9 or only
| looks like it ...
| tssva wrote:
| Maybe next they can work on getting people to stop calling
| Category 3 - 8 cables Ethernet cables.
| TomWhitwell wrote:
| A favourite paper: " A Microfluidic D-subminiature Connector" "
| Standardized, affordable, user-friendly world-to-chip interfaces
| represent one of the major barriers to the adoption of
| microfluidics. We present a connector system for plug-and-play
| interfacing of microfluidic devices to multiple input and output
| lines." https://pmc.ncbi.nlm.nih.gov/articles/PMC3786702/
| Previous discussion:
| https://news.ycombinator.com/item?id=32886596
| overgard wrote:
| Well, I admire the nerd logic, but it seems like it would just
| unnecessarily cripple sales if people searching for it under the
| common name can't find it.
| bjourne wrote:
| This is exactly the kind of technical pedantry I keep coming back
| to HN for.
| androiddrew wrote:
| I love these sparkfun boards. I built this little web app just to
| be able to play with them in the browser too
|
| https://webserialconsole.com/
| sneak wrote:
| If everyone calls something by a name, that's its name, whether
| you like it or not. "ask" is now also a noun.
|
| I spent years wishing (and pretending) that this wasn't the case,
| but you can't fight the wind.
| nailer wrote:
| 9 pin D connector sounds clearer, and doesn't waste a letter. D9
| works for the same reason.
| chillingeffect wrote:
| While we're at it, RS-232 is not serial. It's a voltage
| specification.
___________________________________________________________________
(page generated 2025-07-25 23:00 UTC)