Panasonic KX-TG4221N Service Manual page 18

KX-TG4221N/KX-TG4222N/KX-TG4223N/KX-TG313SK/KX-TG4224N/KX-TG4225N/KX-TGA421N
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  P101  C121, C122  R121, R122  IC501 (25, 24).
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.
BBIC
25
IC501
24
C121
R121
C122
R122
C120
18
L1T
Telephone
SA101
Line
L1R
P101
"FSK"
data