Panasonic KX-TSC10HGW, Service Manual

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11.5. Caller ID Detect Circuit
11.5.1. Function (FSK signal)
The caller ID is a chargeable ID that the user of telephone circuit obtains by entering a contract
with the telephone company to utilize a caller ID service. For this reason, the operation of this
circuit assumes that a caller ID service contract has been entered for the circuit being used. The
data for the caller ID from the telephone exchange is sent during the interval between the first
and second rings of the bell signal.
The data from the telephone exchange is modem signal and modulated in FSK (Frequency Shift
Keying) format. Data 0 is 1200Hz sine wave, and data 1 is 2200Hz sine wave. There are two types
of message format: the single message format and plural message format. The plural message
format allows transmitting the name and data code information in addition to the time and
telephone number data.
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