Panasonic KX-TC1743B Service Manual page 55

Call Waiting Caller ID
Calling Identity Delivery on Call Waiting (CIDCW) is a CLASS service that allows a customer,
while off-hook on an existing call, to receive information about a calling party on a waited call.
The transmission of the calling information takes place almost immediately after the customer is
alerted to the new call so he/she can use this information to decide whether to take the new call.
Function:
The telephone exchange transmits or receives CAS and ACK signals through each voice RX/TX
route. Then FSK data and MARK data pass the following route.
Telephone Line CN1(A, B) C11, C12 R14, R15 DSP (38~40).
. If the unit deems that a telephone connected in parallel is in use, ACK is not returned even if
CAS is received, and the information for the second and subsequent callers is not displayed on
the portable handset display.
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