1.4 and POTS line sharing

Greetings all,
I’ve got a 1.4.21.2 running on SUSE 11.0 and it works generally well except for this. I’ve got a TDM410P card running four lines in FXO status.
CLI> zap show channels
Chan Extension Context Language MOH Interpret
pseudo DID_trunk_1 default
1 DID_trunk_1 default
2 DID_trunk_1 default
3 DID_trunk_1 default
4 DID_trunk_1 default

The problem I have is that when asterisk starts or picks up a zap line, my parallel telco PBX does not recognize the line as busy. Asterisk can also “pick up” this line if it is busy. This leads my receptionist to tell me a few times a week that she is getting “chatter” over incoming calls.

This is my zapata.conf
[trunkgroups]

[channels]
;context=from-zaptel
context=line1
busydetect=yes
busycount=4
hanguponpolarityswitch=yes
usecallingpres=yes
priindication=outofband
signalling=fxs_ks
echocancel=yes
echocancelwhenbridged=yes
faxdetect=incoming
echotraining=10
rxgain=8.0
txgain=4.0
callgroup=1
callerid=asreceived
hidecallerid=yes
pickupgroup=1
context=incoming
priindication=outofband
signalling=fxs_ks
channel => 1-4

this is my dialplan (in part)
[globals]
NIGHTOP => 107
ENGCELL => 5551212

[general]
autofallthrough => yes
static => yes
writeprotect => no
clearglobalvars => yes

[default]
include => parkedfeat
exten => s,1,Answer()
exten => s,n,Verbose(Ringing )
exten => s,n,Gotoif($[ “${NIGHTOP})}” > “108”]?401)
exten => s,n,Dial(SIP/${NIGHTOP},20,KktTm)
exten => s,n,Background(record/welcometodebs)
exten => s,n,Background(record/retry)
exten => s,n,WaitExten(5)
exten => s,n,Background(record/pleasewait)
exten => s,n,Dial(SIP/104&SIP/107&SIP/105,20,KktT)
exten => s,n,VoiceMail(108@default)
exten => s,n,Background(vm-goodbye)
exten => s,n,Hangup()
; night operations
exten => s,401,Background(please-wait-connect-oncall-eng)
exten => s,n,Background(number)
exten => s,n,SayDigits(1)
exten => s,n,WaitExten(2)
exten => s,n,Dial(Zap/2/ww${ENGCELL},20)
exten => s,n,Hangup()

Hi

Did you expect to recognise ? You cannot use lines in parallel.

basicly the line must be dedicated to one or the other, or piggy back off the PBX.

Ian

It seemed to be possible. nonetheless. I’ll drop the parallel this week, just wondered if anyone had made the “parallel isolation” work.

Ok

Its possible to connect both to the line, and with the correct hardware it is possible to isolate a line that isin use. This is done by sensing the line voltage so when its about 7 - 10v it is considered in use. This type of cct was common in modems and PDQ machines to this day. But I have never seen it in PBXs or Alog cards.

Ian