[mod.telecom] CO features

goldstein@ALPHA.DEC (Fred R. Goldstein dtn247-3204) (11/06/85)

V5I60 mentioned the Call Pickup group feature, which just about all
PBXs have had for a few years, and asked about putting it on a CO.
As it happens, most COs also have the feature, and offer it to Centrex
customers.  The reason you can't have it among several different
residential lines is because the feature is designed to work within
a single "customer group", which corresponds to a Centrex system.
Residential lines are not grouped; if they were, they'd all be on
one bill, and would have adjoining directory numbers.  Residential
Centrex does exist but it's quite an uncommon luxury.  Pickup between
customers is not done -- imagine the security risk if it got misprogrammed
a bit!  (At least on the DMS-100 CO, the encoding for the group is
bizarre and much to easy to screw up.  I don't know about the 1AESS or
othwer WECo COs.)

When you move between houses served by the same CO, they can move your
phone either in hardware or in software.  While it seems intuitively
obvious to a digest reader that the work will be done in software,
the hardware technique is really quite easy:  The wires all converge
at a single main frame inthe CO, so the technician just has to run
a jumper to tie the line to both residences at the same time.  Then,
when the old one is disconnected, he removes the old jumper.  It takes
less time, in some cases, than doing it in software.  (Who ever said
telephone companies were up to date?)  

It is possible to use software to activate both lines on the same number,
on some COs, but it's not real easy.  On the DMS-100, it's called a
Multiple Apprearance Directory Number, and its acronym MADN is very
descriptive.  A jumper wire is much easier!