Panasonic KX-TD500 System Reference Manual page 1512

2.03 PITS and ATT Test
To verify the status of PITS or ATT the following functions are tested.
Card to be verified
PLC Link (All types of APITS)
HLC DTMF generator (KX-T123235
DLC Link (All types of DPITS)
DTMF generator (All types of DPITS)
DHLC Link (All types of APITS/DPITS)
DTMF generator (KX-T123235, KX-
T7130 and All types of DPITS)
ATLC Link
DTMF generator
ROM
RAM
Function
Card to be tested should be
"OUS" or "FAULT".
and KX-T7130 only)
16-E-4
Remarks