Sharp FO-90A, Service Manual

Page: 40 / 74

FO-90AAR
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
(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
DPON Connecting DC circuit and DP generating
(The circuit is located H: Line connect / Make
in the TEL/LIU PWB.)
L: Line disconnect / Break
DPMUTE Adjust the resistance during make ratio
(The circuit is located H: Muting
in the TEL/LIU PWB.)
L: Muting cancel
TXMUTE Tx route mute circuit
(The circuit is located H: Muting
in the control PWB.) L: Muting cancel
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]
VOL A VOL B VOL C ON-HOOK ICM/OGM ICM/OGM
OUTPUT VALUE (GP02) (GP03) (GP04) Receiving MONITOR PLAY RINGER BUZZER DTMF/DP
X 0 1K 0 0 0 — — HIGH HIGH — —
X 1 10K 1 0 0 HIGH HIGH MIDDLE1 — — —
X 2 39K 0 1 0 MID 1 MID 1 MIDDLE2 — — —
X 3 100K 1 1 0 MID 2 MID 2 MIDDLE3 — — —
X 4 200K 0 0 1 MID 3 MID 3 LOW MIDDLE — —
X 5 300K 1 0 1 — — — — — FIXED
X 6 470K 0 1 1 LOW LOW — — FIXED —
X 7 750K 1 1 1 — — — LOW — —
VOLUME SETTING