[asterisk-users] 911, channel full

[mir shahnawaz]

Hi,

I am trying to implement 911 funtionality in my PBX. A call should
drop if all lines are busy. Here is my context nineoneone from
extensions.conf

[nineoneone]
exten => s,1,Set(SET_EMERG_FLAG=0)
exten => s,n(checkavail),ChanIsAvail(${EMERGENCY_TRUNK})
exten => s,n,Set(EMERGENCY=1,g)
exten => s,n,Set(SET_EMERG_FLAG=1)
exten => s,n(dial),Dial(${EMERGENCY_TRUNK}/${EMERGENCY_NUM})
exten => s,s+2(trunkbusy),GotoIf($[${EMERGENCY}=1]?inprogress)
exten => s,n,SoftHangup(${EMERGENCY_TRUNK}-1)
exten => s,n,Wait(12)
exten => s,n,Goto(checkavail)
exten => s,s+2(inprogress),Congestion
exten => s,checkavail+101(notavail),Goto(trunkbusy)
exten => h,1,GotoIf($["${SET_EMERG_FLAG}"="1"]?3)
exten => h,3,Set(EMERGENCY=0,g)

If all lines connecting to PSTN are busy. I get busy tone upon dialing
911 and following message is generated by CLI.

app_dial.c:1547 dial_exec_full: Unable to create channel of type
'DAHDI' (cause 34 - Circuit/channel congestion)

I would appreciate if somebody help me solve this issue.

Regards

Shahnawaz