Panasonic KX-TG2583B Service Manual page 64

13.8. Calling Line Identification Circuit (Caller ID)
Function:
The caller ID is a chargeable ID which the user of a 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 a modem signal
which is modulated in an FSK (Frequency Shift Keying) format. Data "0" is a 1200 Hz sine wave,
and data 1 a 2200 Hz sine wave.
There are two type of the message format which can be received: i.e. the single message format
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