[HN Gopher] ISDN: The Untravelled Path of Mobile Computing (2015)
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ISDN: The Untravelled Path of Mobile Computing (2015)
Author : todsacerdoti
Score : 25 points
Date : 2021-05-05 16:03 UTC (6 hours ago)
(HTM) web link (blog.gatunka.com)
(TXT) w3m dump (blog.gatunka.com)
| g051051 wrote:
| I had a bonded ISDN setup with my company paying half of the
| fees, back in 1997 or so. I got to work from home, over a rock-
| steady 128kbit connection, on my home Linux PC connected to my HP
| workstation in the office. It was a magical time.
| hlandau wrote:
| I wonder, were there any countries where ISDN BRI became a
| "default" service, i.e. where it was normal for it to be
| installed in every household to the same extent POTS was?
| ahofmann wrote:
| ISDN was used a lot in Germany and was disabled just a few
| years ago. I still remember the agony of getting my Linux PC to
| work with the Fritz!Card (on the ISA bus) to finally be able to
| be online for 3 cents a minute on the Internet. ISDN was really
| fast and extremely stable though.
| LargoLasskhyfv wrote:
| Hehehe. Wrong move :-) Should have used something with either
| a chip from Cologne Chip Design, or the other big asian
| player whose name I can't remember at the moment. Anyways,
| both were way more affordable and had stable drivers.
| Basically looking at what Isdn4Linux, and later HISAX
| supported well.
| the_only_law wrote:
| One thing that still confuses me about ISDN is that despite
| most of it being standardized in a series of ITU
| specifications, I see a lot of phones and other TE's advertise
| support for vendor specific protocols and other standards
| (National ISDN protocols, special 5ESS protocols and later
| things like DSS1)
|
| What I don't get is the signalling is all standardized (LAPD,
| X.25 or maybe Frame Relay at layer 2, and Q.931 at layer 3) and
| the actual data should just transparent to the protocol and
| only relevant to the devie function (I imagine a typical voice
| call would just alaw or ulaw data). So unless there's something
| going in the upper layers of an established call, why the need
| for various proprietary protocols that from the sounds of it
| are incompatible.
|
| There are devices and tools to simulate this proprietary
| protocols, so I suppose in theory I could reverse them, but
| they're either rare to come by or very expensive for a random
| hobbyist such as myself.
| ac29 wrote:
| I seem to recall in the US, there was a narrow window of time
| where ISDN was interesting - one of my parents had an ISDN
| connection to their office installed in our house. Within a
| couple years, the vastly faster ADSL became available followed
| shortly thereafter by cable internet.
| toast0 wrote:
| IIRC, in California, ISDN only had a per minute tarrif (which
| would run at 2x if you used both B channels) and you usually
| had to pay your ISP more too, although I heard after 56k
| modems were widely deployed, you could use one B channel and
| usually get a 64k (both ways) connection for regular dialup
| cost.
| pantalaimon wrote:
| ISDN was pretty prevalent in Germany, but it always would cost
| a premium compared to POTS
| LargoLasskhyfv wrote:
| Not really true from the times I remember, because heavily
| subsidised.
| tibbydudeza wrote:
| Before we got ADSL we had ISDN when our local carrier introduced
| unlimited weekend calling only billing for the first minute as
| long as you never dropped the call.
|
| I used channel bonding so I could get 128K using a Linux server
| as the dialer/proxy as the Windows drivers for the ISDN card was
| just too darn flaky.
|
| Good times.
| the_only_law wrote:
| Heh, I've been doing a lot of reading on ISDN lately, working on
| a user mode ISDN stack myself. Much more than I should tbh. I
| wonder if the ones pictured in the article use BRI or PRI
| interfaces, I'd have to guess PRI personally.
|
| I actually have a phone like that on my eBay watchlist, except
| it's a video phone (using H.320 I imagine) I've been meaning to
| pick it up, I've have a couple unexpected expenses recently.
| icedchai wrote:
| PRI was similar to a T1. I kinda doubt they had that at the
| payphone level.
| the_only_law wrote:
| Perhaps you're right. I was thinking that if this was part of
| a network of pay phones that they would want to be able to
| handle more than just the 2 calls per line an BRI would allow
| with less infrastructure (though I think lower rate calls are
| possible through additional multiplexing)
| hlandau wrote:
| I'd guess it used BRI. PRI would probably have been considered
| too expensive to justify running to a payphone. My guess is the
| BRI socket on that payphone is only operable when you're not
| making a call, so the 2x64k BRI line can be assigned to the
| phone or passed through to that socket.
|
| You're working on a user-mode ISDN stack - this sounds
| extremely interesting! Care to drop me a line?
| https://www.devever.net/~hl/contact
| _joel wrote:
| I recall my dad getting bonded ISDN at his shop years ago
| (1996/7?) the jump from 28.8kbit (x2 56 was just out but only
| supported on some ISPs iirc) to 128kbit seemed like another
| world. So much so I'd lug my own PC down and pretty much spend
| all my Saturdays there. Good times
| cotillion wrote:
| I got very lucky about then when my father got his work to pay
| for bonded ISDN to our house in the middle of nowhere. Being
| able to connect to BBSes at 128kbit was insane.
|
| But the big thing with ISDN and the internet was the latency. A
| bunch of mudding friends brought over their computers all the
| time since they could suddenly play with a latency almost as
| good as the older kids who played from their university dorms.
| aequitas wrote:
| The 2 x 64kbit was nice and all, but being able to surf all
| evening (reduced tariff) on 1 line and have the house phone
| available for incoming calls (for my parents) at the same time,
| that was the game changer for me. No more, "just 30 minutes
| internet tonight kids, I'm expecting an important call", just
| dial in at 8 and start the download manager for the entire
| evening.
| vardump wrote:
| 128 kbps ISDN had just about 40 ms latency. A significant
| improvement to a modem, which had about 100 ms+ IIRC, often a
| lot more, even 500 ms+.
|
| That low latency made ISDN feel fast, sometimes even better
| than the first ADSL 512-1024 kbps modems that used interleave
| error correction method. Interleaving caused latency to be
| about 60-70 ms IIRC, making the higher bandwidth ADSL
| connection feel slower.
|
| Of course then there was 144 kbps IDSL, which was really 2x 64
| kbps ISDN + 16 kbps ISDN control channel.
| jaywalk wrote:
| IDSL was the first "high speed" connection I ever had at
| home. What a dream it was compared to dialup! Always on and
| 3-4x faster than the best dialup connection could do.
| toast0 wrote:
| It feels like you're adding about 30-50ms onto the base
| latencoes here. Are you/were you fairly far from any major
| internet exchanges when ISDN and ADSL arrived?
| vardump wrote:
| IIRC, those were ping latencies to the first hop discovered
| by using traceroute.
|
| ADSL was about 30-35 ms with fast path in use instead of
| interleave.
| toast0 wrote:
| My experience with fast path ADSL was about 8 ms. I don't
| think I was on interleaved ADSL, but interleaved VDSL2 is
| about 20ms.
| vardump wrote:
| Was this in year 2000 or so?
| toast0 wrote:
| I had ADSL1 at 6m/768k fast mode roughly 8ms latency from
| 2004-201x; the latency was pretty much constant (it did
| get slightly better when I replaced my modem after the
| first one died, but the improvement was less than a ms,
| but measurable). ADSL1 didn't change much after release
| afaik, changes came through ADSL2 and VDSL and such. The
| scourge that is PPP over Ethernet did become more popular
| later in the life of DSL though.
| wmf wrote:
| I remember my ISDN having closer to zero latency. It was kind
| of amazing watching Web pages jump onto the screen.
| LargoLasskhyfv wrote:
| Onyl possible in Japan. Because less vandalism (regarding the
| example public payphone pictured there, whith RJ-11 and RJ-45
| sockets)
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