[asterisk-users] Timing cable usage necessity

[Захаров Антон]

Hello everyone.

I have a timing slips errors and I can't understand what source of the 
problem is.
My installation has 2 digium cards: TE420 and TE220 cards in one server. 
There are 3 spans (E1) to PSTN and 3 spans to internal PBS stations - 
normal installation for transit communication.
Span configuration is:
span=1,1,0,ccs,hdb3 #TE420 - first port. To PSTN.
span=2,0,0,ccs,hdb3 #TE420 - second port. To PBX.
span=3,2,0,ccs,hdb3 #TE420 - third port. To PSTN.
span=4,0,0,ccs,hdb3 #TE420 - fourth port. To PBX.
span=5,3,0,ccs,hdb3 #TE220 - first port. To PSTN.
span=6,0,0,ccs,hdb3 #TE220 - second port. To PBX.
I should to say, that PBXs are interconnected through router (doesn't 
know anything about it). So all schema looks like this: 
http://yfrog.com/jjschemaj
Spans 1-5 works fine, but on span 6 (marked bold) I have rising timing 
slips counter.

I think it's appearing because I'm getting a primary timing source on 
span 1 - first port on TE420. But TE220 doesn't use it's span 5 for 
timing source, because it has priority 3, so it could be a sync problem. 
Am I wrong?

I'm started to think about timing cable for syncing timing on first card 
and second. Should I use it?

It's a problem to bought cable in our city (Russia,Moscow). All 
resellers sell only cards. Could I use floppy or IDE cable to 
interconnect cards? As I see in picture of cable, it's a direct 16 pin 
cable.

Does anybody know something about timing cable for different cards? How 
I can solve my problem?
Thanks for attention