CTC Union TRM01, Руководство пользователя

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Chapter 4. Loop Back Testing
25
TRM-01 APR 2000
4.6 BERT local loop back
For a local test , depress the Loc ana loopbk pushbutton or physically
hardwire the T1 link TX to the T1 link RX with coaxial (BNC) cable. Depress
the
Pattern push-button switch. During BERT testing, the local DTE is
disconnected and the DSR line is off. An internal 511-bit pattern will be
generated according to ITU-T and connected to the transmit input of the local
data channel interface. The receive output is connected to the pattern tester. The
tester compares the received and transmitted patterns and detects errors, as
shown in Figure 4-4. (Err LED should be off during successful loop back.)
(
Pattern and Loc ana loopbk depressed)
Figure 4-4. BERT for local test
4.7 BERT remote loop back for system test
For a system test , the remote site CSU/DSU must support CTC's
proprietary remote loop back (Such as TTU-01 or another FT1 Card ) and both
must be in matching frame mode. The local unit will depress both the Pattern
and Rem loopbk pushbutton switches. The entire T1 link may then be tested, as
shown in Figure 4-5.
(
Rem loopbk and Pattern depressed)
Figure 4-5. BERT used for system test
User
DTE
Data
Port
T1
CSU
LOCAL FT1 Card
Generator
Tester
User
DTE
Data
Port
CSU
LOCAL FT1 Card
Generator
Tester
T1
link
Remote
CSU/DSU
loop back
code sent