Today is the day i look at the old exchange to work out if i should attempt to build a 20 line, PC controlled Private Automatic home telephone exchange.
Currently the machine has 24 Line Relays which have 600 ohms / 800 ohms coils.
The Finals were contolled by these reley sets. (only 3 sets shown)
The relays from left top to right bottom are: D (250 ohm / 250 ohm) B (500 ohm / 200 ohm) H (1k) C (125 ohm) then the next row 1A (250 ohm) Z (200 ohm) F (?) X (?)
The fourth Final relay set is shown here
underneath are curious dual coils.
they run from left to right as:
- a b - c d - e f - g h -
impedence of the completeley separate coils pulling in sides A & B are both 1500 ohms
and the last two are called R & T
Along the bottom of this a set of vibrators, chokes, capacitors which made up the ring and tone section.
The back wall of the machine curently has the line termination and battery distribution & fuses, plus a curious ring voltage generator.
The fourth Final relay set is shown here
underneath are curious dual coils.
Operator....
