[Asterisk-Users] How to fix a Blue Alarm?? Line Noise?

Jon Pounder JonP at inline.net
Fri Aug 12 11:06:54 MST 2005



>
> I have the asterisk t1 card providing the timing as I understand it:
> span=1,0,0,d4,ami

make sure the d4/ami match up with what the pbx is expecting. without docs
its impossible to guess.


>
> I found these settings on the legacy PBX as well, not sure if they mean
> anything:
>
> drop pulse: 014
> pause time: 005s
> flash time: 025*50ms
> Orbit recall: 120*10s

these all sound like individual line (channel) settings within the t1, and
relate to how the line behaves when it is converted to an analog fxs/fxo
circuit to talk to an actual physical phone or line.

as far as the t1 signalling goes I think there are only 4 combinations of
the 2 settings so you could try each one on the asterisk end to see if
there is any improvement, but I don't think it would work at all if you
had them wrong.

something else you could try is find some sort of inline csu device - you
may have something, you might try ebay - the verilink txport was one such
device - it does other things, but you can have it sit in the middle of a
t1 and buffer and regenerate the clocking for both sides, it may just fix
the trouble, or if it is showing errors you'll know which side is to blame
for the problems.

This mighty cool device retailed for $3500, but lots were available for
under $20 a while back on ebay, not made any longer unfortunately. It was
actually intended for protected circuit switchover.



Actually just thought of something else - make sure your line build out
settings are roughly correct for the length of cable you have - too high
or too low a signal on the t1 could be causing problems, too high and you
might be getting a strong reflection interfering with the signal, too low
and you might be losing enough pulses to drop a frame. Make sure the cable
isn't running right beside anything like fan motors, air conditioning
equipment, fluorescent lights etc as well - if its an intermittant problem
it could be interference of some sort. Could be something simple too like
running across the floor and people stepping on it.

if the pbx was used for something else before and the cable length is
vastly different (hundreds of feet) now, chances are good the buildout is
set wrong.

since cables are so cheap, make a fresh one and swap it and see if the
problem gets any better.










>
>
> Do these relate to /etc/asterisk/zapata.conf settings like so:
>
> ; A variety of timing parameters can be specified as well
> ; Including:
> ;    prewink:     Pre-wink time (default 50ms)
> ;    preflash:    Pre-flash time (default 50ms)
> ;    wink:        Wink time (default 150ms)
> ;    flash:       Flash time (default 750ms)
> ;    start:       Start time (default 1500ms)
> ;    rxwink:      Receiver wink time (default 300ms)
> ;    rxflash:     Receiver flashtime (default 1250ms)
> ;    debounce:    Debounce timing (default 600ms)
> ;    emdigitwait: Time to wait for DID digits on E&M links (default 250ms)
> (Increase to 500
> ;                 or so if you are not getting all DID digits on your E&M
> link)
>
> Thanks,
> Geoff
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Jon Pounder

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