5
61291004L2-5, Issue 2
61291004L2-5B
Table 3. Protected Loopback Mode
Requirement T1E1.2/99-007R1 (Latching
Loopback)
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Table 4. Cable Type and Temperature Loss Data @ 13.3 kHz
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.
1
Quality Monitor (SW 1-2)
When QUALITY MONITOR (SW1-2) is ON, the
TRDDB monitors the 2-wire loop and 4-wire
customer interface data for errors. Excessive errors
cause a trouble code to be sent to the network:
ASC (4-wire errors) or alternating MOS and
ASC (2-wire errors). Customer data transmission
is automatically restored when the trouble condition
is cleared.
Rate Selection
Only one rate should be selected plus secondary
channel if applicable . Do not select SC if 64 kbps is
selected.
3. TESTING
Testing for the TRDDB is accomplished using the
same test procedures for 4-wire DS0 DP units.
Cable loss data based on wire type and temperature
for the Total Reach DDS Nyquist frequency of 13.3
kHz is listed in
Table 4
.
The ADTRAN TRDDB front panel is equipped with
logic level bantam test access jacks that permit testing
in both directions using a portable test set. Latching
DS0 DP loopback sequences are supported. Choose
NEAR to test toward the customer loop; choose FAR
to test toward the DS0 drop.
In the FAR direction, a DS0 loopback sequence will
loop the DS0 DP directly across the drop. In the
NEAR direction, a DS0 loopback sequence will loop
the unit directly connected to the portable test set.
