Sharp UX-340L Service Manual page 59

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 & receiving level
•
Signal transmission level setting: ATT -8 dB Circuit output: -11 dBm.
•
DTMF transmission level setting: HF -4.5 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
LF -6.5 dBm
TEL MUTE
RCVOL
(The circuit is located
in the control PWB.)
(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
RCVCL
H
L
Note: The DTMF sending listed above is DTMF signal
sending in the handset OFF-HOOK mode.
Speaker volume control signal,
VOL A VOL A VOL B matrix
VOL B
VOL A VOL B
H H
L H
H
L
Handset transfer mute control 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 (during stand by)
L: When monitoring line signal
UX-340L/UX-345L
UX-330L
Description
Volume
DTMF/DP
Middle Fixed/—
high —
RING.
Buzzer DTMF
Receiving
— — —
—
Low Low
L Middle Fixed Middle
—
L High High