Panasonic KX-TG4753B Service Manual page 17

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 → L101, L102 → 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.
Signal Flow
Telephone Exchange
Cordlessphone
Signal Flow
Cordlessphone Telephone Exchange
BBIC
25
IC501
24
Call Waiting Format
CAS: CPE Alerting Signal
Dual Tone of 2130 Hz, 2750 Hz
-15 dBm (900 ohm load)
CAS
80 5 ms
0~100 ms 60 5 ms
R121
R122
C120
17
Continuance Signal
of 1200 Hz (Data "1")
MARK
0~500 ms 58~75 ms
ACK: Acknowledged Signal
DTMF
"D"
ACK
C121
L101
SA101
C122 L102
P101
KX-TG4753B/KX-TG470B/KX-TGA405B
"FSK"
DATA
about 300 ms
(be changed by
Information Volume)
L1T
Telephone
"FSK"
Line
L1R
data