Excalibur ISX 5312, Operation Manual

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Excalibur ISX 5312/5314 T-1 Multiplexer Installation and Operation
6-4
Digital Loop Test
The Digital Loop Test isolates the local DTE from the rest of the network. During this
test, the ISX 5312/5314 establishes one loop. It loops its transmit data input from the
DTE to its receive data output to the DTE. RTS is looped as DCD. Marks are
transmitted towards the network in the DS0s assigned to the DTE. This test affects only
the DTE port that is being looped. (See Figure 6-4.)
Transmitter
Receiver
T-1
Network
Local ISX 5312/5314
RxD
TxD
Figure 6-4. Digital Loop Test
V.54 Digital Loop Test
The V.54 Digital Loop Test isolates the remote DTE from any externally connected
device. During this test, the ISX 5312/5314 establishes one loop. It loops its receive
data input from the line to its transmit data output toward the network. This test affects
only the DTE port that is being looped. (See Figure 6-5.)
Transmitter
Receiver
T-1
Network
Local ISX 5312/5314
TDM Bus
RxD = Marks
DCD = Off
CTS = Off
Figure 6-5. V.54 Digital Loop Test