[asterisk-users] Problem: Digium TDM400 with XOptionsFlex - Line Busy

[Thomas Klettke]

Perhaps someone with more experience can help me solve this puzzle:

Asterisk 1.4.18 on a Dell PowerEdge SC440, CentOS 5, 2.6.18-53.1.14.el5,
Digium TDM400 with 3FXO(1-3) and 1FXS(4)

Phone service is provided by XO Communications via their XOptionsFlex
service (5 analog lines, 3 of which are used by Asterisk).
For simplicity I refer to them as xx43, xx44, and xx45 - based on their
phone numbers. They are connected to the Digium as follows:

xx43 = FXO 1
xx44 = FXO 2
xx45 = FXO 3

Here is the problem: 
When I connect the Asterisk box to the analog lines the first two lines
(xx43 and xx44) will instantly switch to "busy". xx45 works fine -
incoming and outgoing calls work as expected.

I had XO check the lines - all three lines are programmed the same in
their equipment. The work OK - until they are connected to the PBX -
when xx43 and xx44 instantly switch to "busy". 

I checked the lines with an analog phone: Each line wokred fine when I
plug an analog phone into it.

I suspected that my FXO ports 1 and 2 may be bad. Thus I connected FXO 3
- which is working with xx45 - to line xx43 and then xx44: They went
"busy" right away in either case. 
I connected FXO 1 and then 2 to line xx45: Worked fine both times.

I replaced the entire TDM400 with another card, and repeated the above
tests - the results were the same as above. 

>From those experiments I think I can rule out that the card is
defective, as every FXO channel works with line xx45. None of them work
with lines xx43 and xx44.

I finally replaced the Digium card with a Sangoma A200 with 4 FXO ports
(using 1-3 while leaving 4 unused). All 3 lines work as they should.

Does anyone have an explanation for this strange behavior? 
Any suggestions on how to fix it? I would like to get the Digium card to
work with this setup as I need the 4th (FXS) port for an analog
extension in the office.

/etc/zaptel.conf:
fxsks=1-3
fxoks=4
loadzone = us
defaultzone=us

/etc/asterisk/zapata.conf:
[channels]
musiconhold=default
usecallerid=yes
hidecallerid=no
callwaiting=no
threewaycalling=yes
transfer=yes
echocancel=yes
echotraining=yes
signalling=fxs_ks
context=incoming
group=1
immediate=no
channel=>1-3

; Internal phone:
signalling=fxo_ks
context=internal
group=2
channel=>4

Thanks for your assistance!
Thomas