Xerox FaxCentre F110, Service Manual

Page: 156 / 204

General Procedures / Information
6-70 12/04 FaxCentre F110
Clip impedance
The clip impedance is presented on the line on request by the signal LIU_CLIP. It is composed of
one DC impedance of 100kOhms and one AC impedance connected between a and b.
Figure 1
During On-Hook configuration some Calling Line information may be received by using CLID han-
dling. To enhance the reception of this CLID information the line characteristic has to be adapted
by activating a specific CLID control signal (
LIU_CLIP ).
Line sensing
Incoming Ring (On-Hook)
To signal the Terminal Equipment, whether an incoming call is pending, a ring signal is generated
at the line by the network.
Figure 2
The ring signal is specified by its amplitude, its frequency and the cadence (On- and Off-time re-
lationship). The ring signal transmission is terminated when a valid loop current is detected by the
network. The ring amplitude is added to the line On-Hook voltage.
C802
LIU_CLIP
A and b after
diode bridge
C8xx
R804
R806
R807
Z803
Q808
LA, LB
Ring On-time
[V]
max. On-Hook
min. Off-Hook
Ring Off-time
Ring Phase