[asterisk-users] Clocking Multiple T1 Cards

[Rich Adamson]

Shaw Terwilliger wrote:
> [ I originally sent this to the list last week but it never arrived;
>   it may have been stuck in moderation because the sending address is
>   not my subscribed address.  I apologize if you get this twice. ]
> 
> I have a Digium TE205P connected to two channel banks in my Asterisk.
> PBX.  I will be installing a Sangoma A101 to be connected to a PSTN PRI
> in the same box.  How should I go about configuring the T1 timing for
> these spans?  Right now my zapata.conf contains span definitions like
> the following:
> 
> span=1,0,0,esf,b8zs
> span=2,0,0,esf,b8zs
> 
> If I understand the timing comments correctly, using 0 for both spans
> causes Asterisk to supply the timing for them, which I can't do with a
> PSTN PRI (right?).
> 
> Should I anticipate any problems with this kind of configuration?  Will
> I have to configure the Sangoma card in a special way, or reconfigure
> the Digium card?

All of the above should be rather well documented on the wiki.

The span parameters tell your card which span to use for syncing the 
card's clock. So, you'll want to pick the PRI span as your source for 
clock sync (regardless of whose card you are using).

The transmit side of every T1/E1 "always" includes the clock sync by 
definition and you don't have any choices as to whether you are going to 
generate sync signals. That's true regardless of whether the other end 
of the T1/E1 has a pbx, channel bank, or whatever connected to it.

The "0" clock sync simply means "don't use this span for syncing the 
clock on your asterisk T1/E1 card". A "1" means "use this span first", 
and a "2" means "use this span if 1 is not available or has failed".

If you only have a single PRI to sync to, then you should not use a "2" 
for this parameter.