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Table 3. Model 3551 DSU Jumper Straps
Strap
Designation
State of
Jumper
Strap Function
J12 Left V.35 Test Mode Indication:
Left — Enables V.35 Test Mode Indication
(Pins 1 and 2).
This is the factory default.
Right — Disables V.35 Test Mode Indication (Pins 2
and 3).
J13 Left EIA-232-D Test Mode Indication:
Left
— Enables EIA-232-D Test Mode Indication
(Pins 1 and 2).
This is the factory default.
Right
— Disables EIA-232-D Test Mode Indication
(Pins 2 and 3).
J20 Left Alarm Monitoring (used with the –48 Vdc Central Office
Power Unit):
Left
— Disables the –48 Vdc alarm monitoring
function (Pins 1 and 2).
This is the factory default.
Right
— Enables the –48 Vdc alarm monitoring
function (Pins 2 and 3); the NMS adapter cable is
being used for alarm monitoring.
J21 Right Alarm Monitoring (used with the –48 Vdc Central Office
Power Unit):
Left — Enables control of alarm monitoring via the
NMS adapter cable (Pins 1 and 2); the NMS adapter
cable is being used for alarm monitoring.
Right
— Disables control of alarm monitoring via the
NMS adapter cable (Pins 2 and 3); a standard
EIA-232 cable or the NMS adapter cable is being
used for the diagnostic channel.
This is the factory
default.