Servus,
There are actually multiple FOSS Softmodems.
This one, for example, is based on spandsp:
https://github.com/proquar/asterisk-Softmodem
This one was written by myself and handles the data-link protocoll of
BTX for error-free communications:
https://github.com/Casandro/btx_modem
It's also just 527 lines of code with the only external dependency being
Asterisk.
Then there's also IAXModem, but that's mainly aimed at Faxes.
There's actually a big advantage of using software based modems over
hardware based ones. With IP-Telephony it is vital to have proper
clocks. Unfortunately many bad ATAs have really bad clocks. So your
sender might send out its voice with 8010 Hz sampling rate, while the
receiver might run at 7090 Hz That means that eventually you will have
buffers running over and samples being thrown away. This is very bad for
modems and one of the reasons why T.38 was invented. However with a
software based modem you can just send a packet of data for every packet
you get, so essentially, if it isn't converted to TDM in the middle,
you'll adapt to the speed of the ATA.
(The obvious sane solution to that would of course be to simply use NTP
to determine the frequency error of your system and then adjust your
sample rate so it'll be precisely 8kHz on average. However sane people
usually don't work in that field because of SIP)
Servus
Christian
Hello,
i read about this project that i found quite exciting in it's goals:
http://lists.osmocom.org/pipermail/bbs-revival/2018-January/000003.html
With a friend during the (very limited) spare time we're developing a
pure python modern based SIP/RTP/G711 wardialer, to let younger
generation get having fun with old school phreaking stuff.
Because of the DSP modem related complexities, we've decided to focus
only on:
- Fast signaling scanning of phone prefixes to find existing phone numbers
- Fast scanning on existing phone numbers by recording some 10-15s of
audio, then processing it
It will be something like:
./wardial.py -h sip-hostname -p port -u username -p password -c parallel
channel -r range-XX-XXX (or --input numberlist) -o logfile --fast (fast
scan to check which number exists without looking for carriers)
--wait-between-calls --timeout
However the final goal would be also to hook a software modem to make an
handshake with the remote modem, grab the banner but also provide a
virtual serial interface to let play with the remote system using
minicom or whatever terminal emulation software.
But there's no softmodem and easy to be hooked piece of code to do it,
until now, as i saw this lovely project recovering linmodem.
I wanted to share our goals as will be keeping an eye on the project
where the linmodem/voip/virtualserial integration could be a really nice
companion to complete a modern wardialing kit for 2018 :-)
-naif
Hi there!
I just stumbled on this list, it seems like the project just started, yes?
I was a frequent BBS user in the 90's and still "call" (by telnet) BBS' from time to time, most frequently a BBS in Finland (it's on a VPS these days so I'm not sure it's actually hosted _in_ Finland anymore) called Haciend El Bananas. I recommend it, it's focused on ANSI art and bullshit-chat and there might be some files to download also but I'm not so interested in that anymore so I don't keep track. I use Syncterm to call those boards that use MS-DOS character graphics, it works pretty well. Regular *nix shell telnet can connect too but the ANSI will look like vomit.
Fidonet isn't the only BBS echo active out there, on the top of my head I can remember Agoranet, Retronet and Zeronet (for the elite! ;)).
I didn't have access to internet when Usenet was still a thing so I'd also be interested in some Usenet/UUCP revival. I check som NNTP news from time to time but the traffic is real low nowadays if you go outside the binary groups.
Outside household python scripting I can't code but I can contribute something else eventually I hope.
Cheers,
Ola
