[Asterisk-Users] ISDN master clock issue ?

[Tristan]

I 'll make some tests with a TE210P and see what happens, I'll post as 
soon as I have results...

Asterisk is planned to be at the end of every PRI connection, providing 
voip to the PBX and IVR to the customers calling on the 2 E1 lines 
connected to Asterisk ...

The MATRA PBX is connected to its own E1 line and Asterisk is directly 
connected to a secondary S2 bus.

Setting this S2 bus to be a slave cannot be done easily as we have to 
manipulate tables inside the Matra PBX...
I don't know how to do that...

Anyway I'll test it and see what happens,
but if I understand well to be totally sure there'll be no troubles I 
should buy a Sangoma card no ?


Rich Adamson a écrit :
> Tristan wrote:
>> The fact is that I have 2 different E1 (euroisdn) providers and an E1 
>> (euroisdn) connection to a Matra PBX...
>>
>> The PBX needs to be master and as far as I know the PSTN providers 
>> needs it too...
>>
>> So I want to be sure that the quad E1 card I'll buy will work without 
>> troubles in this kind of setup...
>>
>> Can I only put the synchro to the PBX and forget about the PRI 
>> providers ?
>
> No.
>
> It is highly unlikely the PBX truly needs to be master. If that were 
> an actual requirement, the vendor would never be able to sell their 
> PBX into "any" environment where they connected to a E1 provider. The 
> telco providers "never" slave their equipment from a customer-owned 
> PBX. You will need to find the option in the Matra PBX to define it as 
> syncing from the E1. (In fact, I'd bet a small amount of money the 
> default implementation in the PBX is to sync from any attached E1.)
>
> There is a 99.99% probability the two E1 providers obtain their clock 
> sync from a higher level (hierarchical source), and are already in 
> sync with each other. If you use a digium card, you select one of the 
> providers as your "first choice" sync source, and the second provider 
> as your second choice sync source when the first choice provider's E1 
> is down.
>
> You definitely want your digium/sangoma card to support the 
> hierarchical design of the digital network, and that well known design 
> requires you to sync from your upstream provider, and pass that sync 
> along to your downstream PBX. If you don't do that, calls originating 
> from the PBX and passing through the digium/sangoma card to the PRI 
> network will incur clock slips (out of sync). If the clock slips are 
> too great, you will experience clicks, etc, during a call. Also, if 
> all the components are not in sync, any use of modems (eg, faxes or pc 
> modems) will be significantly degraded if not impossible to use.
>
>
>
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