Paradyne 7511 technical manual Troubleshooting, Symptom Possible Cause Recommendations

Troubleshooting

If the 7511 Dual DSU does not turn on the OK LED after its power-up self-test, refer to the following table.

Symptom	Possible Cause	Recommendations
No power, or LEDs	H The power supply to the	If other devices in the carrier are
are not solidly lit.	carrier has failed.	functioning, ensure that the card is
	H The card is not seated	completely seated in the rear
		connector plate and that the
	properly.
		connector plate is tightly fastened to
		the carrier backplane.
Power-up self-test	The DSU has detected an	H Reset the card by pulling it
fails. Only the Alarm	internal hardware failure.	slightly out of the carrier then
LEDs are on after		replacing it.
power-up.		H Contact your service
		representative.

An Alarm LED is on.

DDS Mode:	H Verify the subscriber loop rate.
H The subscriber loop	H If the NS LED is lit:
rate is not matched to
	± Verify that the DSU is
the 7511's configured
	connected to the network
rate.
	± Request a CSU loopback from
H No DDS Signal
	your network service provider
LADS mode:	Configure both units to the same
H The 7511 configured rate	rate.
does not match its
partner's rate.
Crossed pair connection.	Check interface connections and
(LADS mode only: If the RX	cable.
leads are connected to
each other, the NS LED
also will be on.)
One of several other alarm	H If the OOS LED is lit:
conditions exists:	± Check the status of the remote
H Out of Service	DSU
	± Initiate a Remote Loopback
H Out of Frame
H Bit errors detected	H Try a different DSU with the
during loopback test	same network connection. If the
(which also causes an	problem persists, contact your
Out of Frame condition)	service representative.

12 January 1999 7511-A2-GN10-10