Rainbow Electronics DS26504 - Manual (Page 44)

DS26504 T1/E1/J1/64KCC BITS Element
44 of 128
Table 8-1. T1 Alarm Criterion
ALARM SET CRITERION CLEAR CRITERION
Blue Alarm (AIS)
(Note 1) Over a 3ms window, five or
fewer zeros are received Over a 3ms window, six or more zeros
are received
D4 Yellow Alarm (RAI)
(T1RCR2.0 = 0)
Bit 2 of 256 consecutive
channels is set to zero for at
least 254 occurrences Bit 2 of 256 consecutive channels is
set to zero for less than 254
occurrences
Japanese Yellow Alarm
(T1RCR2.0 = 1)
12th framing bit is set to one
for two consecutive
occurrences
12th framing bit is set to zero for two
consecutive occurrences
ESF Yellow Alarm (RAI)
16 consecutive patterns of
00FF appear in the FDL 14 or fewer patterns of 00FF hex out of
16 possible appear in the FDL
Red Alarm (RLOS)
(Also known as Loss of Signal) 192 consecutive zeros are
received
14 or more ones out of 112 possible bit
positions are received, starting with the
first one received
Note 1: The definition of Blue Alarm (or Alarm Indication Signal) is an unframed, all-ones signal. Blue Alarm detectors should be able to
operate properly in the presence of a 10E-3 error rate, and they should not falsely trigger on a framed, all-ones signal. The Blue Alarm
criterion in the DS26504 has been set to achieve this performance.