done a diagnosis on the DHLC8 card and a fault appears to showing up after port 4..can any one advise? thanks..

***Card Test***
Card:04
Type:DHLC8
**Test Start!**
<<< Local loop back diagnosis >>>
Executing : Local TSW point ---> OK
<<< Card CT Bus diagnosis >>> ---> OK
<<< DTMF Receive test port >>>01 ---> OK
<<< DTMF Receive test port >>>02 ---> OK
<<< DTMF Receive test port >>>03 ---> OK
<<< DTMF Receive test port >>>04 ---> OK
<<< DTMF Receive test port >>>05 ---> OK
<<< DTMF Receive test port >>>06 ---> OK
<<< DTMF Receive test port >>>07 ---> OK
<<< DTMF Receive test port >>>08 ---> OK
<<< PT loop back diagnosis >>>
Cch port01
Primary circuit ---> OK
Dch port01
Primary circuit ---> OK
Bch port01
Primary circuit ---> OK
Cch port02
Primary circuit ---> OK
Dch port02
Primary circuit ---> OK
Bch port02
Primary circuit ---> OK
Cch port03
Primary circuit ---> OK
Dch port03
Primary circuit ---> OK
Bch port03
Primary circuit ---> OK
Cch port04
Primary circuit ---> OK
Dch port04
Primary circuit ---> OK
Bch port04
Primary circuit ---> NG (0x01)
ASIC (PT I/F) ---> OK
Cch port05
Dch port05
Primary circuit ---> OK
Bch port05
Primary circuit ---> OK
Cch port06
Primary circuit ---> OK
Dch port06
Primary circuit ---> OK
Bch port06
Primary circuit ---> OK
Cch port07
Primary circuit ---> OK
Dch port07
Primary circuit ---> OK
Bch port07
Primary circuit ---> OK
Cch port08
Primary circuit ---> OK
Dch port08
Primary circuit ---> OK
Bch port08
Primary circuit ---> OK
**Test End!**