Sharp UX-108 Service Manual page 52

UX-108U/178U/188U
FO-375U
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 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 & receiving level
•
Signal transmission level setting: ATT -10 dB Circuit output: -12
dBm.
•
DTMF transmission level setting: HF -3.5 dBm
Thus, set the level.
•
Attenuation in the LIU section of the receiving level is degigned at
-6 dBm. (The modem and circuit error are not included.)
7. 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
RCVOL1
RCVOL2
(The circuit is located
in the control PWB.)
VOL A
VOL B
(The circuit is located
in the control PWB.)
TXCONT
(The circuit is located
in the control PWB.)
GAIN-C
(The circuit is located
in the control PWB.)
BZCONT
(The circuit is located
in the control PWB.)
5 – 9
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
RCVOL1 H
RCVOL2 L
Three stage switching.
Note: The DTMF sending listed above is DTMF signal
sending in the handset OFF-HOOK mode.
Speaker volume control signal,
VOL A VOL B matrix
VOL A VOL B
H H
H L
L H
L L
TXOUT mute signal
H: Signal sending, when transmitting
L: During reception, transmission mute,
(during standby)
Reception gain switching signal
H: When connected to line, 1: 1 gain
L: When not connected to line, HIGH gain
Speaker output signal switching
H: Buzzer signal output
L: When monitoring line signal
Description
Middle
DTMF sending and LOW
L L
H L
RING./
Buzzer DTMF
Receiving
— — —
High —
High
Middle — Middle
Low Fixed Low