General DataComm SpectraComm 800 T3, Руководство по установке и эксплуатации

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Diagnostics Diagnostics Overview
4-4 SpectraComm 800 T3 Data Service Unit 076R160-000
Installation and Operation Manual Issue 4
Payload Loopback Test and Line Loop Test
A T3 Payload Loopback commands the DSU to loop the received T3 signal back to the remote after
the network framer circuit. The remote site is responsible for test pattern generation and checking.
Payload loopback tests everything on the network side up to and including the unit. It re-generates
framing and corrects bipolar violations.
A T3 Line Loop commands the DSU to loop the received T3 signal back to the remote at the
network interface. The remote site is responsible for test pattern generation and checking. See
Figure.
Note
Remote units cannot place master units in test.
Figure 4-3 Payload Loopback Test
Figure 4-4 Line Loopback Test
SC800 T3 DSU
Tx DRIVER
ANALOG
RECEIVER
T
3
N
E
T
W
O
R
K
F
R
A
M
E
R
DTE
INTERFACE
NETWORK INTERFACE
SC800 T3 DSU
Tx DRIVER
ANALOG
RECEIVER
T
3
N
E
T
W
O
R
K
F
R
A
M
E
R
DTE
INTERFACE
NETWORK INTERFACE