These are recordings of the equipment working in live telephone exchanges - they were made many years ago before digital exchanges replaced them!
cfc_test_mono :
Coin & Fee Checking equipment being tested. This is the sound of an automatic tester running a test routine on the equipment that was used to count coins being put into telephone kiosks.
meters :
This is the sound of mechanical meters stepping each time a call is answered or a call unit has been spent during a call. Each clck was worth around 5p to the telephone company!
ringer45 :
This is the ringer rack being played around with. The machines on the rack provide the tones and pulses needed by the exchange. They also provide alternating current used to ring the telephone bells when a call is made.
strowgr2 :
This is the background sound of a 10,000 line Strowger exchange during a weekday.
uax13_2 :
This is the background sound of a rural exchange during a Sunday afternoon.
xbar_ate :
This is the background sound of a busy city center Crossbar Exchange.