After testing a bit with our security lines and some various ATAs, I believe I’ve found a configuration for burglar alarms, credit card lines and stamp machines to use somewhat reliably. So far I’ve found it to just work, but we are on a fiber connection using VoipInnovations. Although it seems to work well for us, it may not be as reliable on a less-than-solid ISP connection (i.e. cable).
Asterisk, whether DTMF is set to inband or rfc2833, somehow interferes with the communication of the dtmf codes that are technically sent in-band by the security panel, credit card line, etc.
Using our virtual hosting provider, I created an extra FreePBX 12 with Asterisk 11 server and added the following parameter under Asterisk SIP Settings -> Other SIP Settings (at the bottom):
directrtpsetup = yes
This new server I’ve spun up we are considering to use solely for the purpose of credit card lines, stamp machines and security panels where we find the service address to have a connection that is reliable for it to work well.
I have the trunk, extension, and even the ATA configured for DTMF to be sent inband. The SIP settings on the server are NAT = no, canreinvite = yes, and each extension is set to the same - NAT = no, canreinvite = yes.
I have almost exhausted my testing, but each time with these settings, I can trip our security alarm (in test mode), watch it call out for an alarm event, and when I dial the code to cancel the alarm I can watch it call out. No retries. I call the monitoring center and they received our signal correctly.
What are your thoughts? Has anybody else had luck with something different for security, credit cards.