Dahdi T1 trunk to fxs port won't hangup -gives busy signal

Asterisk Asterisk Support
1

This part worked but broke:

Started with Asterisk 1.6.0.6, dahdi 2.1.0.4+2.1.0.2, libpri 1.4.9 on PBX in a Flash distribution.

I have a TE110P card with a T1 line going to an Adtran TSU600e channel bank with 16 FXS ports. Originally using fxo_ls signaling. I can call from a SIP phone to a POTS phone connected to the Adtran port and vice versa without a problem. The issue is if I hangup the call from the SIP phone, the POTS phone receives a busy signal.

The solution was to run fxo_gs (ground start) signaling and then dahdi released the line and the Adtran unit was happy (me too!). Here is the adventure that I’ve documented on what I’ve tried and what finally worked: http://pbxinaflash.com/forum/showthread.php?t=7314. <= PLEASE READ THIS LINK!

Upgrade Broke it:

Unfortunately, I upgraded to dahdi 2.2.0 and I was back to the same problem, where the line was not released and received a busy tone. I’ve since upgraded to the latest version of dahdi 2.3.0 and have the same problem.

Here’s my /etc/dahdi/system.conf (I’ve tried esf,b8zs also) - I have 9x T1 ports, the first 8 are PRI ISDN, the 9th goes to the channel bank.

span=9,0,0,d4,ami
#termtype: NT
fxoks=193-208
unused=209-216
echocanceller=mg2,193-216

Here’s /etc/asterisk/chan_dahdi_additional.conf

;;;;;;[7804100001]
signalling=fxo_ks
pickupgroup=
mailbox=7804100001@default
immediate=no
echotraining=800
echocancelwhenbridged=no
echocancel=yes
context=from-internal
callprogress=no
callgroup=
callerid=device <7804100001>
busydetect=no
busycount=7
accountcode=
channel=>193

The Adtran unit is configured for FXS loop_start and corresponding span config - dahdi_tools indicates the everythings good and green on the T1 card’s LEDs. Just can’t receive a proper hangup with versions 2.2 and 2.3.

When I configure the T1 line for ground_start with the dahdi 2.2 and 2.3 versions, dahdi_tool reports that all Tx_ for each channel are 1s. With version 2.1 (which worked), it would show TxA=0, TxB=1, TxC=0 and TxD=1.

Please read the above documented link of things that I’ve tried. Thanks

2

Further testing with dahdi 2.3.0 - dialing and voice worked but hangup again gives busy signal on POTS phone:

  1. In /etc/dahdi/system.conf used d4,ami with fxo_ks
  2. In pots extension: busydetect=yes, busycount=3, callprogress=yes
  3. In /etc/asterisk/chan_dahdi.conf busypattern=500,500 progzone=us
  4. Changed to esf,b8sz - no difference
  5. In /etc/asterisk/chan_dahdi.conf, added inbanddisconnect=yes, priiindication=inband, relaxdtmf=yes, progzone=us, answeronpolarityswitch=yes, hanguponpolarityswitch=yes
  6. Changed to fxo/gs in /etc/dahdi/system.conf, extension config and the channel bank config for the POTS line
3

Tried to downgrade to dahdi 2.1.0.4+2.1.0.2 (that’s the version that worked) but that just broke asterisk as now in the /var/log/asterisk/full log file it reports that “chan_dahdi.c: Unable to get parameters: inappropriate ioctl for device”… :cry: