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From: Dan Cross <crossd@gmail.com>
To: John Floren <john@jfloren.net>
Cc: The Eunuchs Hysterical Society <tuhs@tuhs.org>
Subject: Re: [TUHS] Anyone have a modem wired up?
Date: Wed, 27 Oct 2021 14:51:05 -0400	[thread overview]
Message-ID: <CAEoi9W6+Y9P+D845urKbDunioj+kUDbxLm-U+5SLUFyfV9w_-w@mail.gmail.com> (raw)
In-Reply-To: <hVNrWEDc6WJqGY4EFFCZUmrG0kAG5PzVkSPPmpcNiCid9VMTVKTGqjYbuTgpOkn97bOnQzCQD1LD0wEGBjYvrOSHWE63oqa0PX12DqTtAFQ=@jfloren.net>

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On Wed, Oct 27, 2021 at 2:31 PM John Floren <john@jfloren.net> wrote:

> On Wednesday, October 27th, 2021 at 11:17 AM, Chris Hanson <
> cmhanson@eschatologist.net> wrote:
>
> > Obihai makes some decent, cheap-on-eBay, unlockable/hackable analog VoIP
> boxes that work just fine with not-super-fast modems. You won’t get 56K or
> even 33.6, but 9600-14.4K should be fine and a Telebit Trailblazer probably
> would be too if you want to use UUCP over dialup…
> >
> > — Chris
>
> I've got a Grandstream HT801 through my ISP (Sonic.net) which works fine
> for voice, and it previously did ok with the modem, but now when I try, I
> start to get garbage soon after the connection establishes (see
> http://jfloren.net/noise.jpg for an example). It happens regardless of
> who I connect to, and seemingly without regard for the connection
> speed--although at 9600, the garbage fills up the screen quite rapidly
> compared to a rather sedate trickle at 4800.
>

My guess is that the codec it uses is optimized for human speech and gets
confused by the range and levels of data modulation.

My modem-fu is rather weak, so if anyone recognizes what's going on, please
> let me know. I worry that it's just a noisy phone connection, but I was
> under the impression that modems had some sort of error-correction built in
> (this is a SupraFaxModem 288).
>

This depends very much on the modem. It might be painful, but I wonder what
would happen if you tried it at 1200 or even 300 baud (assuming those are
simple AFSK using two tones as in Bell 103 and 202 schemes).

        - Dan C.

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      reply	other threads:[~2021-10-27 18:52 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-23 23:43 John Floren
2021-10-24  0:56 ` Warner Losh
2021-10-24  1:29 ` Kenneth Goodwin
2021-10-24 15:36 ` Dan Cross
2021-10-24 16:14   ` Jon Steinhart
2021-10-24 16:37   ` Larry Stewart
2021-10-24 16:51   ` Dr Iain Maoileoin
2021-10-27 18:17 ` Chris Hanson
2021-10-27 18:29   ` John Floren
2021-10-27 18:51     ` Dan Cross [this message]

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