Sharp FO-50, Service Manual

Page: 58 / 102

FO-50RA
FO-70RA
5. Externally connected TEL OFF HOOK detection circuit section
•
The circuit current detection is turned on together with OFF HOOK
of main body or OFF HOOK of externally connected TEL. ON of
CML OFF (HS=L) is judged as OFF HOOK of externally connected
TEL.
6. CI detection circuit
•
CI is detected by the photocoupler which is integrated in series in
the primary side TEL circuit well proven in the existing unit.
5 – 10
Signal Name Description
CML Line connecting relay and DP generating relay
(The circuit is located
H: Line make
in the TEL/LIU PWB.)
L: Line break
SP MUTE Speaker tone mute control signal
(The circuit is located
H: Muting (Power down mode)
in the TEL/LIU PWB.)
L: Muting cancel (Normal operation)
Handset reception mute control signal
TEL MUTE H: Muting
L: Muting cancel
VOLUME SETTING
LINEOUT A
(HIGH) (LOW)
DTMF Transmission Fixed
volume setting (Receiver)
Key buzzer volume setting
Fixed
Speaker volume setting Low 1 1
Middle 1 0
High 0 1
Ringer volume setting Low 1 1
Middle 1 0
High 0 1
DTMF speaker volume setting Fixed
4) Signal selection
The following signals are used to control the transmission line of TEL/
FAX signal. For details, refer to the signal selector matrix table.
[Control signals from output port]