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From: wheels%mks@math.waterloo.EDU (Gerry Wheeler)
Newsgroups: comp.dcom.telecom
Subject: Submission for comp-dcom-telecom
Message-ID: <8707141857.AA21000@mks.UUCP>
Date: Tue, 14-Jul-87 14:57:39 EDT
Article-I.D.: mks.8707141857.AA21000
Posted: Tue Jul 14 14:57:39 1987
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Path: mks!wheels
From: wheels@mks.UUCP (Gerry Wheeler)
Newsgroups: comp.dcom.telecom
Subject: distributed key system info wanted
Keywords: distributed key system
Message-ID: <281@mks.UUCP>
Date: 14 Jul 87 18:57:38 GMT
Distribution: na
Organization: Mortice Kern Systems, Waterloo, Ont.
Lines: 58


We are going to have our operations distributed between two buildings, a
short distance apart (but not adjacent -- the intervening public roads
prevent running wires between buildings).  We would like to find a
telephone system which will span the two buildings transparently.  For
example, people using the intercom shouldn't have to know whether the
destination is in the same building or not, and people in either
building should be able to answer incoming calls (especially when the
system is set for night service). 

We currently have an electronic key system with features such as hands
free intercom, paging, and busy lamps on all stations, and we would like
something similar.  We expect a maximum size of 16 to 20 stations total,
and maybe 5 CO lines. 

So far, we have seen three solutions.  One is to run all the CO lines
into building A, which would have a (electronic) key system.  Then,
using several single line interfaces, station outputs would run from
system A to building B, likely via leased lines.  The phones in building
B would be standard desk phones.  They would be able to access the
system's features by dialling special codes, but they wouldn't have
features like hands-free intercom, busy lamps, etc.  The second solution
is to put another (electronic) key system in building B, which would see
the station lines from system A as CO lines.  Unfortunately, this does
not give the desired transparency.  For example, the two intercom
systems remain completely independent.  The third solution we have seen
is to use electronic systems which are designed to be tied together. 
The IBM-Rolm Redwood system is one of these.  The two systems operate as
equals, rather than master/slave.  However, even then there are failings
in the transparency of operation.  For example, the intercoms are not
integrated, and calling an extension on the other system still involves
going through local dial tone, getting remote dial tone, and dialling
the remote extension. 

It would seem technically feasible to have two electronic systems which
pass data and voice back and forth over leased lines, such that they
share a common view of the world.  By continually updating each other as
to the status of their stations and lines, all stations' indicators
would reflect the status of the whole distributed system.  In addition,
when calling a remote station, the originating system could send data to
the remote system indicating which tie line is being used for voice, and
to which extension it should be routed.  In such a system stations
connected to either system would have equal access to all other
stations, and features like busy lamps would operate correctly for all
stations and lines.  (As a bonus, if this system could also provide a
few 9600 bps serial lines between the buildings, we would really be
set!)

If someone could point us in the direction of a system to integrate the
two buildings, for a reasonable cost, we would be most appreciative.  Of
course, responses on unreasonable systems will be read with interest
too.  We'll summarize whatever information we get. 

-- 
"Network XXIII. Where two's company, and three's an audience." -- Max Headroom

Gerry Wheeler                  {seismo,decvax,ihnp4}!watmath!mks!wheels
Mortice Kern Systems Inc.