[Asterisk-Users] Channel Bank Frustrations

[Andrew Kohlsmith]

On Sunday 20 June 2004 17:51, George Pajari wrote:
> The zaptel configuration is:
>     span=1,0,0,esf,b8zs

Clock from the channel bank.  1,1,0

> The channel bank settings are:
>     Clock source: On or Off, seems not to make a difference
>     Framing: ESF
>     Line Code: B8ZS
>     CSU: On or Off, seems not to make a difference

Set the AB1 clock source to on.  Not sure about the CSU; I don't recall having 
that jumper setting on my AB1.

> The remaining possibilities are:
>  a) a bad channel bank (although it passes the self test)
>  b) a bad zaptel configuration

If you plug in a T1 loopback cable into the T100P does it go green?  It 
should, regardless of clock setting.

Similarly if you plug a T1 loopback cable into the AB1 it should go green too.

T1 loopback cable: 1&4, 2&5.

> P.S. - What, exactly, is the meaning of the second argument to the zaptel
> span parameter ("timing source") and how does it relate to the clock switch
> on the channel bank as I have tried all four combinations without obvious
> consistent affect?

The T100P framer can take timing from the incoming T1 or time to an internal 
8kHz clock.  This sets where the T100P attempts to get its clock source from.  
0 means the framer takes its clock from the internal 8kHz clock; 1 means that 
the framer tries to lock on to the incoming T1.  Typically you want *1* thing 
providing clock and everything else trying to sync to it.  With a T100P it's 
a no brainer; if the other end is pretty much any kind of telco gear capable 
of generating clock, use it instead of the internal source.  :-)

Regards,
Andrew