Xerox Phaser 6180MFP Service Manual page 177

Phaser 6180MFP Multifunction Printer Service Manual
Telephone Call Mechanism
There are two types of telephone line corresponding to the two ways of
transmitting the phone number. They are known as dial types. Most recent
telephones can automatically distinguish the dial type.
One type is "Pulse Dialing (PD)," also called "Dial Pulse (DP)." After the rotary
dial on a dial phone is rotated, the dial returns to its original position. While
returning, the electric current is interrupted (dividing the signal into pulses) the
number of times corresponding to the number dialed. The switch derives the
number from the number of pulses. When the pulse repetition rate is ten
pulses per second, it is referred to as 10PPS (Pulses Per Second), when
twenty, 20PPS.
The other type is known as "Tone Dialing (TD)," formally called "Dual-Tone
Multi-Frequency (DTMF)." Each button on a push-button phone is assigned a
unique pair of frequencies (the "tone"), from which the switch derives the
number.
Pulse Dialing & Tone Dialing
Pulse Dialing
"3, 5, ...... "
Switch
Tone Dialing
"3, 5, 2, ...... "
Switch
5 .........
3
3 5
DTMF Matrix
1209Hz 1336Hz 1447Hz
High Frequency
Theory of Operation
2 .........
697Hz
770Hz
Low
Frequency
852Hz
941Hz
s6180mfp-103
2-95