CTC Union TRM01, Руководство пользователя

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Chapter 4. Loop Back Testing
24
TRM-01 APR 2000
4.4 Data port local analog loop back
The FT1 Card local analog loop back is established in analog mode as
close as possible to the T1 line, to check the satisfactory working of the FT1
Card and the connection between the DTE and FT1 Card . This returns the
transmit signal of the Data port to the receive path of the Data port. The Data
Port must receive its own transmission, therefore we recommend never doing
this test when the data port is ET10 Ethernet bridge or collisions may result.
(
Loc ana loopbk depressed)
Figure 4-2. Data port local analog loop back
4.5 T1 link remote loop back
The local FT1 Card signals the remote unit into digital loop back to
check satisfactory operation of the local FT1 Card , remote CSU/DSU and the
link between. If the User DTE is replaced with a BERT tester, the data cable,
FT1 Card , remote CSU/DSU and T1 link may all be tested.
(
Rem loopbk depressed)
Figure 4-3. T1 link remote loop back
User
DTE
Data
Port
T1 to Remote
CSU
LOCAL FT1 Card
User
DTE
Data
Port
CSU
LOCAL FT1 Card
T1
link
Remote
CSU/DSU
loop back
code sent