1-9. OPERATIONAL MODES AND CONTROLS. (CONT)
INCOMING CALLS WITH MODE SELECTOR SWITCH IN AC SUPV POSITION (CONT)
The tone is sent when the hookswitch contacts change the polarity of the input to the release timer circuit. This energizes the release
timer, the output of which goes to the release oscillator circuit and the send amplifier.
The oscillator is tuned to the 2600 Hz release frequency. The release signal is sent to the send amplifier. Here the signal is amplified
After the signal passes through the ring acknowledge tone detector circuit, the output energizes the 570 Hz integrator circuit. The
output of this circuit is coupled to the timer circuit, which removes the release signal from the send amplifier.
The switching facility which is not receiving a release signal stops sending the 570 Hz release acknowledge signal to the telephone set.
This allows the integrator to return to its normal off condition.