ADTRAN warranty Total Reach DDS-DP Bidirectional Loopback Support, Total Reach DDS Trouble Code

	Table 2. LED Indication
Indicator	Description
SX	ON indicates no sealing current present
	on the local loop; check for continuity
	and proper DDS termination at remote
	end (TR DDS-R).
SYNC	ON indicates that there is no sync
	between the TR DDS-DP and the remote
	TR DDS-R; check for continuity, load
	coils, and other abnormal line
	conditions.
NE CRC	ON indicates that there are errors on the
	incoming data stream; check for the
	abnormal line conditions closer to the
	TR DDS-DP (NEAR END).
FE CRC	ON indicates that there are errors
	occurring towards the remote TR DDS-
	R; check for the abnormal line
	conditions closer to the TR DDS-R
	(FAR END).
QM	ON indicates that a Quality Monitor
	Disconnect has occurred.
DSU	Yellow indicates the absence of the
	customer DSU/CSU as determined by
	the TR DDS-R. Disconnected
	DSU/CSU, invalid framing pattern, or
	no RX signal from the DSU/CSU
	triggers a yellow LED.
	Green indicates presence of the customer
	DSU/CSU as determined by the TR
	DDS-R.
MAN	ON indicates rate has been manually
	selected using SW2.
LBK	ON if DSO loopback is active,
	OR if a DS6 session is active.
	FLASHING if OCU loopback active,
	OR if TR DDS-R has activated TR
	DDS-DP loopback toward customer.

DS0 DP units. The Total Reach DDS-DP only responds to latching DS0 DP loopback sequences.

NOTE

If 64 kbps is selected, the unit will only respond to latching loopback sequences. Alternating sequences are not valid at this rate.

Total Reach DDS-DP Bidirectional Loopback Support

The Series 5 Total Reach DDS-DP will execute a bidirectional loopback when performing a DS0 loopback, as shown in Figure 4. This allows a standard portable DDS test set, connected to the 4-wire customer interface of the Total Reach DDS-R, to verify the integrity of the 2-wire loop by transmitting a test pattern and examining the returning data for synchronization and errors. The Series 5 Total Reach DDS-DP LBK indicator will illuminate during this test mode.

Series 5

TR

DDS-DP

Intra-officeCustomer

DS0

Bidirectional loopback

Figure 4. DS0 Bidirectional Loopback

The Series 5 Total Reach DDS-DP also responds to a loopback command sent by the Total Reach DDS-R when the LBK button on the Total Reach DDR-R is pressed. This allows loop testing to be performed from the remote end without test center coordination. The SLC Series 5 Total Reach DDS-DP only performs a loopback towards the customer in this case. The latching and alternating loopback sequences are defined in Table 3 and Table 4.

Total Reach DDS Trouble Code

The Total Reach DDS system is designed to provide a quick diagnosis in the case of a circuit condition where continuity is broken. The trouble code type received by a tester determines whether the open condition is occurring on the local loop or at the customer premises. In the event of an open conductor or disconnected 2-wire loop, the Total Reach DDS-DP transmits an alternating ASC/MOS trouble code into the network as shown in Figure 5. In the event of a 4-wire open or disconnect, the TR DDS-R sends an ASC to the network as seen in Figure 5.

Remote End Initiated LBK Tests

The Total Reach DDS-DP supports loopbacks generated from the TROCU-R which allow testing to be performed without coordination with the CO or test center. Loopbacks initiated by the TROCU-R front panel LBK pushbutton aid in system turn-up testing or troubleshooting from the remote end.

4 Section 61433105L2, Issue 4 61433105L2-5D