I’m running Asterisk 1.4 with a TDM400 card (Zapata drivers) and whenever I call my PSTN line from my cell phone, the tones are only recognized about maybe 5% of the time if I’m lucky. The rest of the time, the system would just hang up on me.
I tried Asterisk 1.6 (Dahdi drivers) and ran into the same issue.
I tried changing the Rx gain for the PSTN channels, but still no go. I have read a lot about this issue, but nothing has worked for me.