asterisk users - Feb 2006 - T1 Channel splitting PRI/data not working

I'll keep asking weird questions here:

I have two T1 WAN circuits originating at my asterisk box and 
terminating at Asterisk servers at remote sites.  Currently I use zaptel 
ppp assigned to all 24 channels for data.  Now I would like to split off 
a few of these channels for voice trunks (I should use VOIP, but at the 
moment I do not have fast enough servers for the codecs)

At one site the split work perfectly, with 8 channels for voice and 16 
for data. Oddly enough the second site, using the exact same asterisk 
configuration (I just imaged the disks and am using the same hardware), 
doesn't work if the channels are split (the PRI and the PPP fail to come 
up) but does work if all 24 channels are assigned to PRI or data.

I've always suspected this T1 line has some problem (large data 
transfers occasionally timeout, and I sometimes catch packet loss under 
high load), but I don't have any good ways of testing it.  The phone 
company tests to their smartjacks and claims everything is great, but 
the smartjack is a long way from the equipment and I don't trust the guy 
that did the wiring too much.  This line was once used for a frame relay 
circuit and repurposed, whereas the working line was installed as a bare 
point to point circuit from the start.

Two questions, is there a way using the zaptel hardware to view T1 line 
errors and the like?  Or is there anytime else that could cause it to 
work as a whole connection but not channelized?  (Something weird like 
channels not having the same number on each end..I wouldn't think that 
was possible)

Only other idea I have is to find a T1 BERT and test the line.

--/etc/zaptel.conf--
#Span 1  T1 to Building 1 (This way works)
span=1,0,0,esf,b8zs
clear=1-24

#Span 1  T1 to Building 1 (This doesn't work)
#span=1,0,0,esf,b8zs
#clear=1-8
#bchan=7-23
#dchan=24

#Span 2  T1 to Building 2 (This works)
span=2,0,0,esf,b8zs
clear=25-32
bchan=33-47
dchan=48
--snip--

Thanks
Mark

For the poster place a test jack on the end that connects to the smart
jack. Make it as so:
Pin 1	-> 4
Pin 2 -> 5


This document will explain how to use the zaptel tools to run a pattern
loop on a zaptel interface (T1) with an external hard loop.

Please have a T1 loopback plug or jack with cable available.
The pin out should be pin 1 -->4 and pin 2 -->5.  
Make sure the span is in OK (no alarms) then configure the span as
follows in zaptel.conf: 

span = 1,0,0,esf,b8zs

clear = 1-24

Then run ztcfg -vv to configure the channels.  The channels must be
configured for esf/b8zs and each span needs it's own clear = x-x line. 

Now you can build and run the tests. 

cd /usr/src/zaptel
make tests

./patlooptest /dev/zap/1 60
Going for it...

Thanks go to Neil Lewis @ Digium Technical Support for this document.








Info about lines config and reasons why things may not work deleted. 
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