Sharp FO-77 Service Manual page 56

FO-77U
UX-66U
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.
7. Signal/DTMF transmission level
•
Signal transmission level setting: ATT -10 dB Circuit output: -12
dBm.
•
DTMF transmission level setting: HF -3.5 dBm
Thus, set the level.
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]
Signal Name
(The circuit is located
in the TEL/LIU PWB.)
SP MUTE
(The circuit is located
in the TEL/LIU PWB.)
LF -5.0 dBm
TEL MUTE
(The circuit is located
in the control PWB.)
VOLUME SETTING
Receiver volume setting
DTMF Transmission
volume setting (Receiver)
Key buzzer volume setting
Speaker volume setting
Ringer volume setting
DTMF speaker volume setting
5 – 10
CML Line connecting relay and DP generating relay
H: Line make
L: Line break
Speaker tone mute control signal
H: Muting (Power down mode)
L: Muting cancel (Normal operation)
Handset reception mute control signal
H: Muting
L: Muting cancel
Handset receiver volume control signal
Volume High
RCVOL
RCVOL L
Note: The DTMF sending listed above is DTMF signal
sending in the handset OFF-HOOK mode.
Low
High
Fixed
Fixed
Low
Middle
High
Low
Middle
High
Low
Middle
High
Description
Low DTMF sending and LOW
H H
LINEOUT A RCVOL
(HIGH) (LOW)
1
0
1
1 1
1 0
0 1
1 1
1 0
0 1
1 1
1 0
0 1