On Wed, Oct 27, 2021 at 2:31 PM John Floren 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.