Hello Leonard!

May 06 01:15 03, Leonard Erickson wrote to Bo Simonsen:

 LE>> Using the T-1 as a "raw" data pipe instead of
"formatting" it into 
 LE>> the 24 B channels and a D channel.

 LE>> With 24B+D "formatting", you may only get 24*56k
(1.344mbps) or at
 LE>> most 24*64k (1.536 mbps).

 BS>> The most normal is 30B+D, here in Denmark. Or 2B+D (normal ISDN).

 LE> Well, in the US the T-1 is defined as 24B+D.

Ok.

 BS>> But actually can one D channel handle so mutch? As far as i know 
 BS>> isn't it more than 9600 bps. I can see it's enought to handle 
 BS>> signaling, caller-id transfering, etc. But to 30B channels? 

 LE> Remember, the D channel is only needed for call setup and tear-down.

Yep

 LE> *During* a call, there's no signalling for that B channel. Well, maybe
 LE> if you've got Call Waiting, or the version that incorporates Caller ID
 LE> for the second incoming call. 

That's right. But i think of if they were used for normal telephone
traffic, it sounds of a quite low speed.

 LE> But even that only takes a small bit of 
 LE> data.

Yeah.. 

 LE> In some places in the US, in the early days of ISDN you could send 
 LE> data
 LE> over the D channel from your ISDN gear. Data *other* than the call
 LE> setup etc. 

I heard about it.. Was it cheeper than using the B channels, or was there
any other advantages of it?

 LE> I'm pretty sure about the 16k, as (for various reasons) the phone
 LE> company likes "even" numbers like that. I'd have to do
some digging,
 LE> but I seem to recall being corrected by a telco engineer about that 
 LE> in
 LE> an echo or a newsgroup a while back when I said 9600. 

Ok

Regards,
Bo

--- Msged/LNX 6.1.2