<html><body><div style="color:#000; background-color:#fff; font-family:arial, helvetica, sans-serif;font-size:12pt"><br><span>Hi<br><br>I've looked for a good tutorial on spanDSP but haven't found
one. In my former message I've talked about the way the modems have to
connect each other and exchange some informations.<br><br>I'm still looking for a good tutorial about spanDSP,<br>I
need to know if what I've described in my former message about de
connection between the two modems is a standard processus or not and if it is
not, how I can use spandsp library to program a correct one for my
needs.<br><br>Thanks in advance...<br><br>Tony</span><span style="font-style: italic;"><br></span><div><br></div><span style="font-style: italic;"><br>>On 08/06/2012 06:46 PM, 8hector8 wrote:<br>>> Hello everybody,<br>>><br>>> Here is my issue. I need to simulate a modem transaction in C. It's a V.21<br>>> modem in 200 bits/s. This modem dial a number and waits for an "request to<br>>> send" sent by the reciever. This is where I have to simulate a modem.<br>>> The "request to send" is composed of a 2100 Hz tone for 2,4 secondes and 32<br>>> alternations of two tones :<br>>> 1650 Hz and 1850 Hz, 15 ms each.<br>>> In my idea, streamFile() function seams to be the good mean.<br>>><br>>> The real issue is that when those tones are sent, the transmeter will send a<br>>> "message" which is 16 digits in V.21 mode. 8 data bits, no parity, 2 stop<br>>> bits.<br>>> 200 bits/s
means that each tone is 5 ms. 1180 Hz is a "1" and 980 is a "0".<br>>><br>>> So, I need to get those 16 digits messages from tones back into numbers. So<br>>> I need a way to listen the signals and analyse them and this is where I<br>>> don't know how to do it.<br>>><br>>> Maybe, I have to create a module into freeswitch and here also I need an<br>>> help to do it.<br>>><br>>> Thanks for your attention.<br>>><br>>> Tony BECQ<br>>The V.21 modem in spandsp can easily be modified to work at 200bps. <br>>There are setups in there for 110bps and 300bps. Just add another table <br>>entry to 200bps. Wrap that in some endpoint code, rather like the FAX <br>>modem stuff, and you're pretty much there.<br>><br>>Steve<br>></span></div></body></html>