Panasonic KX-TD500 System Reference Manual page 1514

3.01 Loopback Test (LBT) - for T-1/E-1
Description
Used to verify the validity to T-1/E-1 cards and line connections.
Command Format
(1) OPE>LBT + Item1 + Item2
(2) OPE>LBT + Item1 + Item2 + Item3
Command
Format
(1)
(2)
* 1 Loopback test is done automatically inside the T-1/E-1 card.
2
* Loopback test is done between the T-1/E-1 card and the external equipment (CSU, DSU).
In this case, loopback mode should be set at the external terminal beforehand.
* 3 When a card No. is specified, DTMF Generator No.1 and DTMF Receiver No.1 of that card are used
for the test.
Result Display
Error Indication
OK
Voice error
Signal error
Item 1
1 or 2
1: Internal
1
Loopback*
2: External
Loopback* 2
Normal
Speech path failure
Control signal path failure
Item 2
101,105,109,
201,205,209,
301,305,309
3
(Card No.)*
G xxxyy
(DTMF Generator No.)
xxx : Card No.
yy : 01 to 06 (T-1)
01 to 02 (E-1)
Description
16-E-6
Item 3
None
R xxxyy
(DTMF Receiver No.)
xxx : Card No.
yy : 01 to 24 (T-1)
01 to 08 (E-1)