Xerox FaxCentre F110 Service Manual page 160

General Procedures / Information
LIU_CLIP:
Clip Impedance Setting Control output signal. The signal is used to select additional line imped-
ance during CLI handling. This signal should be activated only during V23 or DTMF reception.
Gyrator (DC characteristics)
The DC characteristic must be easily customised to fit the needs of TBR21, Eastern Europe
(600ohms), Australia and USA. If possible, two impedance's should be mounted at the same time
and switched by firmware depending on country setting.
The main characteristic is given by the two transistors Q802 and Q803. The transistor Q804 limits
the current rushing through Q802 and Q803. The threshold level for the limitation can be set with
R810, R811 and R808.
High impedance path
The high impedance path enables the codec to listen to the line during on-hook state: clip recep-
tion, CNG detection. The signal is taken between a and b, just after the protection circuitry. The
amplifier Z852 amplifies the signal. The high impedance path is muted during off-hook by the tran-
sistor Qxxx. To switch on/off this path, the voltage is measured in parallel with the DC character-
istics. The threshold level is given by R878 and R876.
6-74
Table 8:
CDIM State
P
1 CLI Line Impedance on
0 Default, Normal Line Impedance
12/04 FaxCentre F110