Ultrix V4.2 sources et al...

From: Michael Sokolov <msokolov_at_ivan.Harhan.ORG>
Date: Tue Mar 9 20:21:41 2004

R. D. Davis <rdd_at_rddavis.org> wrote:

> This is interesting. Why then do DECvoice and Fallon FAX cards, for a
> Qbus VAX, have connectors for a T1 line on them? Not being very
> familiar with telephone equipment with T1 lines, perhaps I'm
> overlooking something. Any thoughts on this?

In telephony applications a T1 is split into 24 channels each carrying a phone
call. When, however, someone speaks about T1 as a dedicated line for Inet, a
device called a CSU/DSU takes the entire T1 payload (all 24 channels together)
and turns it into an EIA-422 or V.35 synchronous serial stream that a router
then has to deal with. In fractional T1 applications the CSU/DSU is
reconfigured to take fewer than all 24 channels, reducing the bit rate on the
EIA-422 or V.35 line.

MS
Received on Tue Mar 09 2004 - 20:21:41 GMT