3 beeps and call is ended

We are having problems with calls received from traditional POTC (regular landline) phones calling our FreePBX 13. Most of these regular POTC phones are connected sharing a line with Fax machines.

We are recording the calls in FreePBX and we noticed that every time a call is dropped, we hear a 3 beep sound and the call is immediately cancelled. We have been searching for answers and apparently those 3 beeps mean CALL CANCEL.

Any idea if there is a way to avoid the call to be dropped from FreePBX side?

Not enough info,

Describe your FreePBX inbound call trunking, SIP or DAHDI?

Are your “POTC”'s phones remote from your FreePBX server, or do you mean POTN’s arriving on your FreePBX,?

Where , relationally are ‘most of’ the faxmachines physically located?

Sorry for not being clear. I meant to say that the calls being dropped originate in regular POTS (Plain Old Telephone Service) lines with an analog phone connected to them. In those regular lines, we are aware that there are other analog phones and analog fax machines sharing the SAME land lines. So we are not sure where those 3 beeps are originating, but the fact is, every time those 3 beeps are heard, the calls is immediately dropped.

We receive those calls in a FreePBX 13 with SIP trunks.

If someone has an idea on how to control this, we will appreciate!

Old days - dinosaurs were setting up phone systems:

Three beeps were used then an “override” or “flash-override” signal was received to terminate a call. In our particular system, this was done to knock everyone off their calls so that “important” calls would have plenty of resources.

For me, it’s too coincidental that you are getting three beeps and your phones are dropping for it to be unrelated. The PBX logs should tell you what is happening.

Those three beeps are almost certainly not coming from Asterisk/FreePBX, I would check the POTS provisioning and circuitry at the point of origination , that would include any “line grabbers” like fire alarms or up line Fax Machines.

Thanks cynjut and dicko.
Clearly those 3-beeps are coming from one of the devices connected to the same phone line, like Fire Alarms, Fax Machines, etc. Have you seen any way to disable these 3-beeps (Terminate call) on FreePBX side? Customer has thousands of locations with this setup, so we are looking to disable that from the PBX side…

If the are coming from a parallel connection, then there is no way to prevent it, Asterisk is not disconnecting the calla and there is no SIP mechanism I can think of that could over-ride .

I have never heard those ‘3 beeps’ , so where are you located , perhaps it is country specific, perhaps it is something his VSP is doing, has he checked with them yet?

Dicko,
Customer has locations all over Texas, Alabama, Mississipi, Oklahoma, Louisiana, Arkansas, New México, Mississippi, Alabama, Georgia,North Carolina, SOuth Carolina and Florida. Most located in small towns. Maybe those towns have older CO equipment…

I doubt it class 5 iron is class 5 iron, I would first check with the VSP why they are sending “hang-up” and compare with your call logs.

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The ‘three beeps’ thing is what you get when (for example) and inter-switch connection fails, or a cell tower goes down. I’ve experienced a couple of times. In my last career, three beeps was the signal that you call has been disconnected at the switch. You’ll get them a lot in areas of natural disasters and places where emergency calls preempt a connection as an override.

I am reasonably certain that Asterisk no facility like this. While SIP (and TCP/IP) both honor ‘flash’ and ‘flash override’ precedence, it’s almost never used “in the civilian world”.

Thanks dicko and cynjut. I’ll check with the VSP.

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