Switching and Switch Control

HUT Comms Lab., Timo O. Korhonen

An early analog PBX: 100 subscriber exchange (Subscriber controlled call set-up)

MAIN PARTS:

- Call finders (CF)

- Group selectors (GS)

- Line selectors (LS)

Call setup:

1. A-sub. picks up handset (CF detects)

- exchange sends line available -tone

2. A-sub. Send pulses (GS, LS activated)

- exchange sends ringing tone

A-subs.

B-subs.