44023-1297 <90-00058>
P
AGE
9
For both incoming and outgoing calls, release of the CCO lead
through Q9 is delayed one second by a delay to release timer.
This makes sure the on-hook tone is transmitted before the CCO
lead releases the radio transmitter.
Clear Circuit
The clear function occurs when:
♦
The phone hangs up.
♦
90 seconds elapse during off-hook.
♦
The call terminates before the phone answers.
When the phone hangs up, a pulse at the reset output (pin 3)
resets the 44020 DTMF Decoder Module and returns the circuit
to its normal condition.
Terminate a call before the phone answers by applying a ground
to the clear input (pin 16). Application of ground returns all
functions to normal and outputs a reset pulse at pin 3. The tone
decoder normally applies the clear input upon receipt of an
on-hook tone.
You can use the front panel TEST/RST switch for card align-
ment. Pressing the button once causes an off-hook condition.
Pressing the button again resets the 44022 SLIM.
P
OWER
R
EGULATOR
S
ECTION
The power regulator consists of two voltage regulators. One
provides -20 VDC to the 44023 circuitry and -22 VDC to the next
regulator. The second regulator provides -10 VDC and -8 VDC to
the 44023 circuitry. Input power can range from -21 VDC to
-56 VDC.
CIRCUIT DESCRIPTION
