[Asterisk-Users] timing/clock problem

[Kevin P. Fleming]

Andrew Kohlsmith wrote:

> Wow you're the first person I've seen using a combination of T1 and E1 on the 
> same card.  I wonder if this has something to do with it (i.e. a bug in the 
> drivers).

Based on my understanding of these cards, I don't think it's possible 
for this to work.

The framer chip on the board will sync itself to the incoming streams 
and recover the data, so that _might_ work. What will _not_ work 
properly is the outgoing streams; all the streams leaving the card are 
clocked using the same clock (either the on-board clock, or the 
currently selected "span" clock).

When you set a span to clock source "1" in zaptel.conf, that makes it 
the preferred transmission clock source for the _entire card_. If that 
span is down, the span marked "2" becomes the source for the card. If 
none of the spans with non-zero preferences are up, the card uses its 
internal source to clock the transmissions.