Xerox Phaser 6180MFP, Service Manual

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Phaser 6180MFP Multifunction Printer Service Manual 2-95
Theory of Operation
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.
s6180mfp-103
697Hz
1209Hz 1336Hz 1447Hz
770Hz
852Hz
941Hz
Pulse Dialing & Tone Dialing
Pulse Dialing
Tone Dialing
Switch
Switch
Low
Frequency
High Frequency
DTMF Matrix
3 5 .........
3 5 2 .........
"3, 5, ...... "
"3, 5, 2, ...... "