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

[Michael Bolton]

Jay beat me too it. Force G.711 and set packetization to 10ms if you can. Also, try in-band audio. Some older alarm panels don't work well with NTE 101. Adtran's don't always pickup every DTMF tone which can result in missing or doubled DTMF tones.

At the end of the day, I would urge the customer to put the fire alarms on cellular communicators. We constantly fight with signals over phone lines. Even if you get it working on your side today, that doesn't mean it will work a month from now if one of your carriers makes a change and backhauls over SIP using a different codec.

Thanks,
Mike



-----Original Message-----
From: VoiceOps <voiceops-bounces at voiceops.org> On Behalf Of Jay Hennigan via VoiceOps
Sent: Monday, February 13, 2023 2:30 PM
To: voiceops at voiceops.org
Subject: Re: [VoiceOps] Alarm panels and how they dial DTMF digits - pots migration from DMS to Metaswitch issue


CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.

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

_______________________________________________
VoiceOps mailing list
VoiceOps at voiceops.org
https://puck.nether.net/mailman/listinfo/voiceops
IMPORTANT NOTICE: This e-mail message is intended to be received only by persons entitled to receive the confidential information it may contain. E-mail messages to clients of Holmes Security Systems may contain information that is confidential and legally privileged. Please do not read, copy, forward, or store this message unless you are an intended recipient of it. If you have received this message in error, please forward it to the sender and delete it completely from your computer system.