[asterisk-users] Issue with PRI connection

A J Stiles asterisk_list at earthshod.co.uk
Mon Sep 24 03:02:47 CDT 2012

On Sunday 23 September 2012, Ashish Agarwal wrote:
> For some reason pri show spans does not show up. Can someone assist me to
> fix this issue.

DAHDI is fussy about its configuration files.  A single misconfiguration anywhere 
can break the whole thing, so get it working with just one span first.

Make sure you set the jumpers on the card correctly for E1 operation  (they 
are often set as T1 on delivery)  and specify the correct channel to use as a 
D-channel  (usually 16 on span 1; 1-15 and 17-31 are the B-channels.  Add 31 
for span 2, and so forth)  and the correct signalling system.  Ask someone at 
your telco if not certain.

Another thing that can go wrong is the cabling from the NTE to the Asterisk 
box.  Sometimes you need a straight-through cable, other times you need a 
crossover.  Usually the active pairs are 4 and 5, and 2 and 1; so you need to 
cross over 1 with 5 and 2 with 4.  Sometimes the polarity on pins 4 and 5 is 
wrong  (this is the only pair with the lower-numbered pin coloured and the 
higher-numbered pin white)  and sometimes the equipment is bothered about 
this, so try also a crossover from 1-4 and 2-5.  Again, ask someone from your 
telco if not certain.

Once you've got span 1 working, bring up the others one by one; and don't be 
afraid to grow your configs with comments where you have commented out lines 
and/or added explanations of what you have changed.  It's always easier to 
take extraneous stuff out later than to try to remember what you were thinking 
before something interesting happened.


Answers come *after* questions.

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