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?
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.
Old days - dinosaurs were setting up phone systems:
Three beeps were used then an âoverrideâ or âflash-overrideâ signal was received to terminate a call. In our particular system, this was done to knock everyone off their calls so that âimportantâ calls would have plenty of resources.
For me, itâs 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 âline grabbersâ 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 sideâŠ
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 â3 beepsâ , so where are you located , perhaps it is country specific, perhaps it is something his VSP is doing, has he checked with them yet?
The âthree beepsâ thing is what you get when (for example) and inter-switch connection fails, or a cell tower goes down. Iâve experienced a couple of times. In my last career, three beeps was the signal that you call has been disconnected at the switch. Youâll 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 âflashâ and âflash overrideâ precedence, itâs almost never used âin the civilian worldâ.