[VoiceOps] Alarm panels and how they dial DTMF digits - pots migration from DMS to Metaswitch issue

[Jay Hennigan]

On 2/13/23 11:15, Matthew Yaklin via VoiceOps wrote:
> Hello All,
> 
> I guess I have an old school question for the list. The question is we are having trouble with alarm panels dialing and our gear collecting the DTMF digits properly. Only from a company ran by a single alarm panel guy who is not terribly helpful. At least 7 different sites are having the same problem on different copper pairs/T1s. Different gear. Etc...

Is the issue that the alarm panels can't complete a call to the central 
monitor, or do they ring in OK and then cant pass DTMF inband once 
connected to communicate the nature of the alarm?

Alarm panels are essentially a form of modem. You might turn on modem 
passthrough and ensure that your codecs are forced to G.711. Other 
codecs don't play well with modem-like applications.

If the DTMF digits used to set up the call are failing, then there's 
likely something out of spec with the DTMF encoders in the alarm panels, 
frequency or twist. Or something different in the call setup like a 
leading 9 for a PBX that no longer exists. What does the sending Adtran 
show for the dialed digits on the call?

Got a Sage 930A gathering dust on a shelf?

Using VoIP or anything that requires local power for fire alarms in 
general is another topic.

-- 
Jay Hennigan - jay at west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV