General Procedures / Information
FaxCentre F110 12/04 6-89
GP 39 Pulse Dial
On-Hook Line Configuration
During terminal equipment On-Hook the PD control signal stays inactive to inhibit a valid loop cur-
rent. Only an idle loop current (On-Hook) is drawn from the network
Off-Hook Line Configuration
The activation of the dial control signal (PD) in addition with the line control signal (HOOK) estab-
lishes a connection between the terminal equipment and the network. To draw a valid loop current
the PD signal (Hook/Pulse Dial control signal) has to be kept activated.
Pulse-Dial
To signal the network to establish a connection between the terminal equipment and another line
equipment, a number of impulses is used to transfer a ‘phone number’ (a defined number of digits)
of the other line equipment to the network. The digits which are used to specify a phone number
are coded by the number of line disconnection’s and reconnections of the PD signal. These volt-
age and current changes a mirrored at the line signals (LA, LB)
Figure 1
The digit of a phone number corresponds to the number of disconnection’s (Break) and reconnec-
tions (Make). A digit ‘3’ has three ‘Breaks’ and three ‘Makes’.
The PD pulse duration relationship of break-time and make-time is country specific.
LA, LB
On -> Off-Hook transition time
On -> Off-Hook
[V]
On-Hook
Off-Hook
max. On-Hook
min. Off-Hook
Break
time
Make time
Pulse Dial
Dial pause
Loop Current
[mA]
Valid Loop Current
min. Loop Current
threshold
Idle Loop Current
No Loop Current
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