I've just resurrected my Asterisk* server. This time I'm running it in a jail, I copied over my old conf files, and most things worked. I never really got my speedtouch 190 going before. This is a little box that has an ethernet port to connect with your LAN, and a phone point for your ordinary phone. It cost me £14 - with £10 of call credit - so a lot cheaper than a hardware SIP phone.
The sticking point was getting Asterisk* to recognise DTMF tones. It worked fine to call an outside line, or to call voicemail - but once a call had started, no DTMF tones would be recognised. The trick is to use RFC 2833. For Asterisk* I had to change sip.conf. Change the line dtmfmode to read:
dtmfmode=rfc2833
For your Speedtouch navigate to the SIP section, and look for the "OOB Signalling" page. Chnage the settings so that they look like this:
