[Asterisk-Users] Multiple E1 configuration question

[Steve Underwood]

Scott Stingel wrote:

>Hi all-
>
>This question is for those familiar with EuroISDN setup.
>
>I have a customer in Europe where I'm going to install an asterisk based
>system with 4 E1's.  The customer will configure them all in one large hunt
>group.
>
>My question is about the E1 channel configuration.  I know that usually
>single E1 spans are set up with 30 channels (1-15 and 17-31) as the voice
>(bearer) channels and channel 16 as the signalling (data) channel.  (I think
>Channel 32 is unused in E1 setups)
>
Channel 32 (actually called 0) is very much used - its does the 
syncronisation and alarm reporting jobs.

>But if there are multiple E1's in the same group, is it typical to have one
>data channel supplying signalling for the entire group?  ...or is there
>usually 1 D channel per E1?  If the latter, is the setup something like
>this:
>
>B channels 1-15, 17-31
>D channel  16
>B channels 33-47, 49-63    
>D channel  48                ...etc...??
>  
>
In T1s they call this NFAS - non-facility associated signalling. 
EuroISDN (pretty much the only form if ISDN on E1s these days) does not 
use NFAS. It is a mix of good and bad - you get a few extra channels, 
but it makes things more fragile. ETSI decided against it.

One odd thing you can hit in some locations is the Telco won't spread 
your hunting group across more than one E1 (or T1 for that matter). Its 
a dumb limitation, but if the telco imposes it there is little you can do.

Regards,
Steve