Panasonic KX-TD500 - Manual (Page 253)

Features
Programming Guide 253
5.8 Waiting Second Dial Tone Code
Used to assign parameters for the Waiting Second Dial Tone feature.
Parameter Entry No.
Default 001-020
Value Range 001-200 in 20 codes increments
Description/Function Specifies the entry number of the Waiting Second Dial Tone codes
which you are going to programme.
Reference None