Module Descriptions, RFL 9508D Digital Section
8.1.12.2
TX, LPBK AND ERR INDICATORS
Three LED indicators on the CM4 module (TX, LPBK and ERR) indicate transmitter output status,
loopback status, and error status. The meaning of each of these indicators appears in Table 8-10.
RFL 9508D UCC
RFL Electronics Inc.
Table 8-12. TX, LPBK and ERR Indicators
Item
(Fig. 8-5)
Module Label Description
15
CM4
TX
Transmit Output indicator (green); indicates transmit status:
ON: Transmission signal is normal. It can be either data, or all ones if the
shelf is idle.
OFF: No signal is being transmitted, indicating a hardware failure.
LPBK
Loopback indicator (yellow). Lights when one or more of the CM4’s three
T1 loopbacks have been activated. View the LPBK group to determine
The active loopback(s):
LNLB: Line Loopback
PaLB: Payload Loopback
EqLB: Equipment Loopback
ERR
Error indicator (red). When frame format is set to ESF, this indicator flashes
once each time a CRC-6 error is detected, and remains on continuously
above a random bit error ratio of about 10-5.
When frame format is set to SF, this indicator flashes once each time a frame
error is detected, and remains on continuously above a random bit error
ratio of about 10-3.
G G G
LOOP INT EXT
G Y R
TX LPBK ERR
G Y R
RX BPV FRM
March 11, 2010
8-19
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