ADTRAN Cable T1 ESF CSU ACE - Manual (Page 41)

Chapter 4. Operation
61202066L1-1B T1 ESF CSU Rackmount User Manual 41
Figure 4-11. Local DTE Loopback
Remote Loopbacks
When a remote loopback is chosen, a code is sent towards the network that
is intended to loopback the far-end T1 ESF CSU RM. These loopbacks
will be either line (LLB) or payload (PLB) as described in the section
Local Loopbacks on page 39. Some of these codes are sent out-of-band in
the ESF Facility Data Link (FDL -4 kbps control channel) and some are
sent in-band. The FDL codes work only when in ESF mode. The AT&T
INBAND LLB does not require the FDL and may be used in SF or ESF
mode.
Test Patterns
The T1 ESF CSU RM can send three different data patterns to the network
for testing the T1link. The ALL ONES pattern sends all 1s in every
channel of the Tl. The ALL ZEROS pattern sends all 0s in every channel
of the Tl.
The 1 IN 8 pattern sends a fixed pattern where one out of every eight bits
is a one. When a pattern is started from the terminal, a test results screen
displays a count of Code Violations (CV). If the pattern is started from the
DATAMATE, then the CV total is found under the TEST RESULTS
selection. The CV total is cleared when the test is initiated.
NI CSU
NETWORK
DTE LB
DTE
DTE INTF
T1 ESF CSU RM
LINE
INTERFACE FRAMING
DEVICE