Xerox FaxCentre F110, Service Manual

Page: 177 / 204

General Procedures / Information
FaxCentre F110 12/04 6-91
GP 40 CURMOD
CURMOD Handling
To get the required waveform on the line (acc. PTT regulations) an additional current has to be
supplied by the LIU during dialling. The CURMOD signal serve this special purpose during Pulse
Dial. The timing relationship of CURMOD and the Pulse Dial port depends on the country specific
regulations.
Pulse-Dial
To enhance the current (switching) characteristics (smaller rising times of the loop current) a cur-
rent enhancement signal is activated during Pulse Dial. This CURMOD signal is activated syn-
chronous with the PD signal during Pulse Dial. The timing relationship is country specific, but
similar.
Figure 1
CURMOD Set-up (General)
In general the CURMOD is activated with the first make and handled like the Pulse dial port in-
cluding the last break, where the CURMOD port is deactivated.
Figure 2
PD
CURMOD
break make
DMO_on
On-Hook Off-Hook
Loop Current
[mA]
Valid Loop Current
min. Loop Current
threshold
Idle Loop Current
PD
CURMOD
break make
DMO_on