Board:   [fsxNet] BBS Software Development/Support
Subject: Re: Zoom Modems [Xpost]
From:    kombos(21:3/255)
Date:    Sat Sep 19, 2026 23:32

 Sh> Now I need someone to test my connection! 986-303-1430.

We did - 24 calls on the evening of 19 September, from Warsaw, a
USRobotics Courier on a VoIP gateway with not one metre of
copper on our side. Your modem answers fine and we reached 14400
with V.42bis, but V.8 never completes between us, so V.34 never
gets a chance. One call in full - spectrum, signalling, packet
stats, audio replay, no login needed:

https://ftn.deadsocket.church/lc/?r=762cfc551d7f16ef7973066d8d95d344

That is the 22:43 call: CONNECT 14400/ARQ/V32/LAPM/V42BIS,
carrier in 45.7 s, 2400 Bd and 1800 Hz both ways, -19.0 dBm in,
-11.5 out, 11898 characters read. One retrain, and it finished
at 12000 rather than the 14400 it started on. We ended it.

Your answer tone is ANSam, not plain ANS: the 2100 Hz carrier
has sidebands at 2085 and 2115 Hz, 20.2 and 20.6 dB down - clean
15 Hz modulation. Your modem announces V.8 correctly. Then it
stalls. From the 22:33 call, our V.8 left on:

  10.5-13.5 s  your ANSam
  14.0-15.0 s  you send JM on V.21 channel 2, we send CM on
               channel 1 - the exchange begins
  16.0-16.5 s  you drop to an 1800 Hz V.32 carrier while we are
               still repeating CM
  21.5 s on    both sides broadband, nothing agreed
  27.5 s       you go back to 2100 Hz and start over

That loops until our S7 expires - NO CARRIER at 64 s, while the
gateway cheerfully reports the call connected throughout.
Turning off V.34 alone changed nothing; skipping V.8 is what
works. ATS56=96 plus ATS54=240 and we land on V.32bis.

WHAT 24 CALLS SAY ABOUT THE LINE

13 connected, 54 %. Speeds 4800 ten times, 14400 three times,
twelve of thirteen with V.42 LAPM. Carrier up in 39.6 to 57.8 s,
median 42.0. Medians across all 24, to us / from us:

  jitter p95       0.82 / 0.88 ms
  jitter worst     2.08 / 1.25 ms
  jitter RFC3550   0.06 / 0.39 ms
  clock drift       +17 / +35 ppm, ~5 ms over a 2 min call

Receive level sat between -19.0 and
-19.3 dBm on ten of the eleven connected calls that reported it
- 0.3 dB of spread across four hours. The eleventh is the odd
one: CONNECT 14400/V32/NONE, no error control, -54.0 dBm, 130
characters, gone 4.3 s later with Loss of Carrier.


THEN YOU BANNED US  ;-)

At 23:34 your gate started saying this instead:

  Synchronet External POTS Support/Win32   v2.1
  Copyright 2025 Rob Swindell
  Connection Rate Exceeded. Try Again Later.
  NO CARRIER

and later just: Access Denied. -Click!-

Until 23:32 every call that held an ARQ link pulled 6 to 13 kB
of EleBBS screen; after that, nothing but the banner. Fair
enough - 24 calls in one evening to somebody else's board is not
neighbourly. We have stopped, and there will be no more from
here unless you ask. We never reached the login screen and did
not create an account.

One question ?
The thread says StarTech 56k USB, Conexant, hardware - but not
what is behind it. Real copper POTS, or an ATA or VoIP service
in the way? If your side is VoIP too, two G.711 legs back to
back would explain a lot about V.8, and that is a more
interesting result than either of our modems. And if they are
handy: what does your modem report after one of our calls, and
what init string are you answering with?

Greetings from Poland,
kombos

--- ENiGMA 1/2 v0.5.1-beta (linux; x64)
 * Origin: DEAD SOCKET CHURCH (21:3/255)
.