I have a ring group with one external destination. The first incoming call works fine. When the next call comes in, an internal phone rings once, the new call is then dropped with the message “all lines are busy”.
This is the ring group definition:
Ring strategy: ringall
Ring Time: 28 (changed that from 10 to 30 seconds - no difference)
Destination if no answer: Voicemail
The installation is for a small office with only 4 internal extensions: 2 phones and 2 headsets connected to a Gigaset 510N.
The only trunk is a Patton Smartnode 4120 device connecting to a legacy BRI line (ISDN connection with the capacity of two calls in parallel).
We have used the same setup for years with a Raspberry PI (RasPBX) without any problems. Same ring group. We only experienced SD Card failures and setup a new virtual server on Debian for better reliability. The phones and the Patton device should hence be ok. I compared all settings to the RasPBX installation and could not find any difference.
Without the external destination, everything works fine.
I found this in the log:
app_dial.c: Called SIP/SN4120/055605555 app_dial.c: SIP/6440-00000057 is ringing app_dial.c: SIP/4416-00000055 is ringing chan_sip.c: **Got SIP response 503 "Service Unavailable" back from x.x.x.x:5060** app_dial.c: **SIP/SN4120-00000058 is circuit-busy** app_dial.c: **Everyone is busy/congested at this time** (1:0/1/0) .... file.c: <Local/055605555@from-internal-0000000d;2> Playing 'all-circuits-busy-now.ulaw' (language 'de_DE') .... pbx.c: Auto fallthrough, channel 'Local/055605555@from-internal-0000000d;2' status is 'CONGESTION' pbx.c: Executing [h@from-internal:1] Macro("Local/055605555@from-internal-0000000d;2", "hangupcall") in new stack .... pbx.c: Executing [s@macro-hangupcall:7] Hangup("SIP/SN4120-00000054", "") in new stack app_macro.c: Spawn extension (macro-hangupcall, s, 7) exited non-zero on 'SIP/SN4120-00000054' in macro 'hangupcall' pbx.c: Spawn extension (ext-group, h, 1) exited non-zero on 'SIP/SN4120-00000054'
Some more background information:
- When the first call comes in, the BRI has etwo lines available. One is used for the incoming call, the second is used for the external destination. Picking up the call from an internal phone will release the 2nd line.
- During one incoming call, we can make an additional outgoing call without a problem.
- When the 2nd call comes in, the BRI has only one line left and can’t reach the external destination. This would be ok for us, but the internal extensions should still be served.
- The voicemail is not launched in the 2nd call - the system simply hangs up
- When the 1st call is picked up by the external destination, all lines are really busy - that’s ok and not subject of my issue