[Asterisk-Users] Two zaptel T1 cards: no clock from one

[Peter Svensson]

On Sat, 4 Dec 2004, Kevin Blackham wrote:

> Yeah, proper crossover cable.  I've eliminated all cabling issues with
> the T1 analyzer.  I get a full and accurate pattern back when I test
> from the cable end where it would have been connected into the T100P,
> with the channel bank in loopback.  The main symptom is that when I
> hook the analyzer directly to either the channel bank or the T100P,
> neither is providing clock.  I could have the channel bank supply one,
> but I will have fax/modem calls bridged between the two PCI cards, so
> a common clock is best.  The most disturbing thing is that the T100P,
> as the only card in a system, provided clock just fine.
> 
> There was a thread last month in -dev about being unable to use common
> clock source across cards.  Is this related?  How can one cause zaptel
> to provide ref clock?  Should I be seeing 1000 interrupts/sec on any
> and all TDM cards?

Yes, you should see a 1000 Hz interrupt rate from both cards. Seeing the 
interrupts does not mean that the card is providing clock. Not being able 
to use a common clock is not a big deal. The cards should still be very 
capable of running voice etc. There is some other problem. 

Given the reports seen here and on the bug tracker lately it seems there 
may be some problem setting up clocking for the second card if it is to 
provide the clock source itself. I suggest you call Digium since the
driver support is included in the price you paid for the card.

For totally accurate multiple spans you need a TE410P or TE405P, at least
for the time being. Those will be bit accurate when bridged. In theory it
may be possible to synchronize several cards but that is all theory at the
moment.

Peter