TELECOM Digest OnLine - Sorted: Re: Hypothetical SxS Question

Re: Hypothetical SxS Question

Carl Navarro (cnavarro@wcnet.org)
Thu, 08 Dec 2005 17:46:43 GMT

On 7 Dec 2005 10:40:16 -0800, hancock4@bbs.cpcn.com wrote:

> This question is purely speculative only, not for real use.

> Suppose we wanted to install a PABX using step-by-step gear in a condo
> complex. We need 250 stations. My question regards the most
> efficient station number assignments.

> One person says the stations ought to have a four digit number that
> corresponds to the apartment number. There are 19 buildings with
> 10-15 units per building. So unit #103 would get phone number 0103
> and unit #1513 would be phone 1513.

> While the above is easier to remember, wouldn't that be a waste of SxS
> terminals and require more switch units without any gain in
> efficiency? Isn't a four digit code inherently more complex than a
> three digit in an SxS environment? I think the phone ought to be
> numbered strictly sequentially, starting from 111 and going upward.

Of course it would waste resources, but on the bright side you'd only
have to clean the first two levels of the connector banks :-) Later
implementations would have used a tranlator and register senders. You
dial 1513 and the translator converted it into 813. The wiring and
troubleshooting of translators and register senders, even in a common
control crosspoint office, would have been a nightmare.

> The Bell System history talks about "graded multiples" to more
> efficiently use trunks and switchgear in central offices, but I don't
> think that would apply in this application.

> Now if we wanted to implement the above using modern technology, would
> only a PC be required with appropriate software and cards? I guess
> we'd need capacity for about five conversations at once.

Or a PBX carded 4x250. The high station count precludes an old analog
Mitel SX-200, but it would have served about 188 stations with 31
calling paths.

> [TELECOM Digest Editor's Note: The problem as I see it with matching
> apartment number to intercom number is a security issue. Do you really
> want to let strangers know that the tenant in apartment 103 (0103) or
> the tenant in apartment 1513 (1513) is or is not at home? With the
> Bell System 'Interphone' (or the competitor's 'Enterphone')
> arrangement, the intercom numbers were used randomly for more security.

In a Viking entry sysem, you assign 2 or 3-digit numbers to a
directory, but those numbers don't relate to anything but storage
bins.

Carl Navarro

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