Comfort has a unique feature called Dial Test which is not found in any other alarm system
This is activated by keypad keys F,3,3 and in Comfigurator > Security > Phone Numbers as shown below
Select the keypad to hear the dial test on.
When dial test is initiated by either method, the dialing sounds are heard on the keypad, starting with the dial tone, the DTMF dialing tones dialing the phone number, the ringback tone, and the initial voice answering. If the number is busy, the busy tone can be heard
In the case of dialing to a Central Monitoring system, you can also hear the handshake tone, the DTMF signal sent to the CMS by Comfort, the acknowledgement tone reply from the DTMF, additional alarm signals from Comfort if there is more than 1 alarm, and the kissoff signal from Comfort.
This is a very useful tool for diagnosing dial to cms issues. If the kissoff signal is hear and comfort hangs up, that means that the signal has been sent to the CMS, and the problem is at the CMS end