Panasonic UF-580 Service Manual page 207

6.2.7 Line Control Circuit
The Line Control Circuit consists of CML relay, DP circuit, DAA (Direct Access Arrangement), Ring Detect
Circuit for power-save and DC hold circuit. A Jack for an external telephone, which can be used for either
an external telephone or an optional Handset Kit. The block diagram of the Line Control Circuit is shown
below.
Line
Connect only to
one module
+
Ringer
IC
-
+
Speech
IC
-
Optional Handset Kit
SC PCB
CML Relay
External
Telephone
Jack
~
~
Hook SW
~
~
Ringer Signal Detection,
TAM I/F,
DTMF Remote Detection
Off-Hook
Detection
10MW
DP
Circuit
DC Hold
Circuit
Ringer Signal
Detector
for Wake-up
(PC2)
MJR PCB
Line Control Circuit
207
DAA DAA
Line Control
I/F I/F
Si3015 Si3021
(IC23) (IC24)
DP Control
PNL
MODEM
MN195006
CPU