Re: ISDN & sound question

Christopher M Sedore (
Mon, 31 Oct 1994 10:10:56 -0500

> I believe that some of the newer ISDN cards allow use of both of the 64K
> channels (that make up the "Basic Rate Interface"), simultaneously.
> However, that requires software at your end and the other end of the ISDN
> link that will support two IP routes to your machine. You'll pay twice as
> much for your connection as well!

This depends on the equipment used. Some ISDN cards bond the channels
together transparently, so they look like 1 128k pipe to the protocols
riding on the channel. There is a spec called BONDING which is supposed
to provide a standard, interoperable method of doing this.

> Also, I was under the impression that the ISDN channel size in North
> America was 54K and not the 64K as it is elsewhere. Is this the case only
> in some areas? ..or is it simply misinformation?

I belive your local access point always supports 64k. The question is
whether the connection from your telco's switch to the switch the other
end connects to can pass the full 64k. If it can't you get 56k per B
channel (not 54k).

See the ISDN FAQ for more complete information.


Chris Sedore
Maxwell School of Citizenship and Public Affairs
Syracuse University