General DataComm SpectraComm 800 T3, Руководство по установке и эксплуатации

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Diagnostics Diagnostics Overview
4-6 SpectraComm 800 T3 Data Service Unit 076R160-000
Installation and Operation Manual Issue 4
Remote Lineloop and Remote Payload Loop Tests
In the Remote Test function, the local DSU transmits an in-band command to its remote DSU,
directing the remote to loop received signals back onto the network. The remote loopback provides
a path through the DSU, the network, and the remote DSU for an externally generated test signal.
Remote Test checks the local DSU, a portion of the remote unit, and the T3 line. During Remote
Loop:
• The DSU transmits the in-band loop-up command to its remote DSU.
• In response to the command, the remote unit performs a digital loopback and loops the
receive signal back to its transmit path.
• The DTE interface of the local DSU remains active.
• A test signal has to be generated and checked externally either by a DTE or by a bit error
rate tester (BERT). Connection at the local site can be made through the DTE interface.
• The device supplying the test signal is responsible for error detection and reporting.
• The loopback remains in effect until the DSU transmits a loop down command to the
remote unit to release the loopback.
Note
Remote loopbacks are for C-Bit Framing only.
Figure 4-6
Remote Line Loopback Test
Figure 4-7 Remote Payload Loopback Test
MASTER SC800 T3 DSU
Tx DRIVER
ANALOG
RECEIVER
T
3
N
E
T
W
O
R
K
F
R
A
M
E
R
DTE
INTERFACE
DTE
REMOTE SC800 T3 DSU
Tx DRIVER
ANALOG
RECEIVER
F
R
A
M
E
R
DTE
INTERFACE
MASTER SC800 T3 DSU
Tx DRIVER
ANALOG
RECEIVER
T
3
N
E
T
W
O
R
K
F
R
A
M
E
R
DTE
INTERFACE
DTE
REMOTE SC800 T3 DSU
Tx DRIVER
ANALOG
RECEIVER
F
R
A
M
E
R
DTE
INTERFACE