Hi Moises,
Thanks for the reply. I have been able to resolve this issue – looks like I had to explicitly choose the modem carrier (1200) using the +MS command.
However, curious to know a bit more on the echo canceller that you are referring to – we are using the Sangoma card with echo canceller, and I haven’t explicitly turned it off!
Echo cancellation is not a good idea in data calls. Mind you, depending on the type of data call there is variable tolerance. Also, some data calls (ie fax) start by sending a well-known tone that Sangoma echo canceller recognizes and then disables itself (see CED tone here: http://telecom.tbi.net/fax-call.htm).
If it's working for you, good :) ... if you start having issues with some calls succeeding some not, now you know another thing to try (turn off the ec).