[BC] Older telephone systems

[Jerry Mathis]

Moving a tad off topic, I used to be fascinated by this kind of thing 
myself. Telephones and telephone exchanges and PBX's were a hobby of 
mine for many years. I installed several different PBX's at a private 
school I attended. The first one was an all-relay system, first 
installed in a bank in Illinois in the 1930's. It had 25 lines, with 
the capability of 2-party lines with ground ringing, 4 city trunks, 
and 6 line-finders. Dial tone was accomplished by a vibrating reed 
relay. Ring voltage at 20 Hz was provided by a weighted vibrating 
reed relay that opened and closed a set of contacts on a transformer, 
switching DC through the transformer primary. Watching it work was 
fascinating. It ran on 24 volts provided by two car batteries in series.

The fun kind of went out of the hobby after even dedicated electronic 
cabinets went out of style, and it all became computerized.

Jerry Mathis

On Wed, May 21, 2008 at 11:16 AM, Paul B. Walker, Jr. 
<<mailto:walkerbroadcasting at gmail.com>walkerbroadcasting at gmail.com> wrote:
No big deal, it's nothing more then a matter of curiosity as to how 
the numbers are assigned to specific towns.