Xerox FaxCentre F110 Service Manual page 165

Off-Hook, On-Hook Configuration
The activation of the hook-switch (HOOK = 1 and PD=1) within the line connection, establishes a
connection between the network and the terminal equipment. Due to the reduction of the source
resistance of the terminal equipment, the loop current (I
dition. The loop current is above a certain threshold as long as the terminal is connected (by de-
tecting a valid loop current within the terminal equipment) or the network is in a valid loop current
state (see also LA, LB On-Hook, Off-Hook Configuration). Due to a hook change, the changing
line voltage may introduce an erroneous ring (RING) signal !
Parallel Terminal Equipment Off-Hook(FCU Off-Hook)
When a parallel terminal equipment, connected directly to the line, goes Off-Hook, it reduces the
line voltage, which results in a drop of the loop current that may be detected.
FaxCentre F110
LA
I
Line
PSTN
Network
U
Line LIU_HOOK
LB
Internal phone On Hook
Figure 2
)rises which indicates an Off-hook con-
Ioop
LB2 LA2
I
Ext Loop
0
1
1 PD
U
IntLoop
Terminal
Equipment
12/04
General Procedures / Information
6-79