Timing cable usage necessity

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Asterisk Users 3 Comments

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

3 thoughts on - Timing cable usage necessity

  • 2010/11/25 Захаров Антон :

    I can’t answer your problem about how you find one in Moscow, but I
    can tell you that when I’ve installed two cards in a single server I
    have used the timing ribbon cable. I have no idea whether it made a
    difference, and I now build my servers differently. You could ask
    Digium directly, as they probably know their resellers.

    Something that may help you is that you can make sure you set the
    priority on the cards differently from each other. There is a dial
    with a pointer that tells you which card is prioritized. Whenever I
    had two in the same server I made sure that one card was set higher
    than the other.

  • As I think, i forgot to set priority on TE420 and TE220. Could this be
    the cause of an slip error?

  • Здравствуйте.

    Спасибо за ответ. Меня какраз интересуют проблемы, которые решает этот
    кабель. Достать его теоретически мы сможем. Другой вопрос, в чем же его
    уникальность? И почему, например, нельзя использовать floppy кабель?
    Когда я поставил floppy кабель вместо “официального” и модулю указал
    опцию “timingcable=1”, у меня либо вообще система падать стала (так, что
    коннект по ssh терялся), либо в asterisk я получал сообщение Bad HDLC и
    поток не поднимался.

    Hello.

    Thank you for your reply. I’m interested in problems that solves this
    cable. We can get it theoretically. Another question, what is its
    uniqueness? And why, for example, we can not use the floppy cable?

    When I put the floppy cable instead of an “official” and set the option
    module “timingcable = 1”, I either do a system has to fall (so that the
    connection was lost over ssh) or I get the message Bad HDLC in asterisk
    and the E1 flow was not raised.