3 Jan
2020
3 Jan
'20
9:06 a.m.
On 02/01/2020 22:56, Harald Welte wrote:
I think that yours is "the right approach" from a technical standpoint
of view.
What we tried to achieve is "something working" by gluing together all
of the pieces, leaving for another pizza-hackaton improvements and
stabilization.
It's *likely* that Asterisk-Softmodem doesn't provide the performance
and stability we want (sometime is connect, sometime it does not
connect, sometime it gives your garbage, anyhow still missing CONNECT
and reporting of negotiated carrier speed).
So the world still miss the missing piece of a features voip-modem that
also provide a pty.
I added osmcom linmodem to the "Software Modem" section
https://github.com/x25today/voipwardialer#software-modem .
This is pretty much what I had in mind, too - although
not specifically for
wardialing, but simply for any use case.
Yes, we also realized that focusing our current and past effort on
trying to get a working "voip-modem" is much helpful than making a "voip
wardialer" (because, for example, beave's iWas could work fine exposing
a pty with basic AT emulation).
The design is
a bit "creative" but it's done a way to make the "Software
DSP" issue pluggable and remote (now Asterisk-Softmodem connected to a local
asterisk).
As you can see at http://osmocom.org/projects/linmodem/issues I had the
plan
to do this based on the linmodem code from Fabrice Bellard (who needs no
introduction). The code implements more different modems/standards than
the asterisk code, and it's not really tied to the winmodem hardware - it simply
consumes and produces 16bit samples, so all that's needed to attach it to RTP
is to do the aLaw/uLaw table lookup.
But hey, my approach is still vapourware and yours is implemented, so who
am I to make suggestions.
We're working to try to make this working with a commandline and
extendit piece by piace, but really without the real
telecommunication-grade effort-and-skills to fix the DSP problem
properly, assuming that someone with that knowledge will help in hooking
one of the cool and complete softmodem.
Linmodem is surely a way to go, we also spotted this nice soft-modem
that by reading the specs seems very very interesting for it's
integration opportunity (connecting pty and audio i/o) and the careful
timing consideration https://github.com/randyrossi/fisher-modem .
Did you ever saw / considered this?
-naif