DS2155 T1/E1/J1

T1 ALARM CRITERIA Table 10-1DS2155ALARM SET CRITERIA CLEAR CRITERIABlue Alarm (AIS) (Note 1)Yellow Alarm (RAI)Over a 3ms window, five or fewerzeros are receivedOver a 3ms window, six or more zeros arereceivedD4 Bit-2 Mode (T1RCR2.0 = 0)D4 12th F-bit Mode (T1RCR2.0 = 1;this mode is also referred to as the“Japanese Yellow Alarm”)ESF ModeRed Alarm (LRCL) (Also referred toas Loss Of Signal)Bit 2 of 256 consecutive channelsis set to zero for at least 254occurrences12th framing bit is set to one fortwo consecutive occurrences16 consecutive patterns of 00FFappear in the FDL192 consecutive zeros arereceivedBit 2 of 256 consecutive channels is set tozero for less than 254 occurrences12th framing bit is set to zero for twoconsecutive occurrences14 or fewer patterns of 00FF hex out of 16possible appear in the FDL14 or more ones out of 112 possible bitpositions are received, starting with thefirst one receivedNOTES:1) The definition of blue alarm (or alarm indication signal) is an unframed, all-ones signal. Blue alarmdetectors should be able to operate properly in the presence of a 10E-3 error rate, and they should notfalsely trigger on a framed, all-ones signal. The blue alarm criteria in the DS2155 has been set toachieve this performance. It is recommended that the RBL bit be qualified with the RLOS bit.2) ANSI specifications use a different nomenclature than the DS2155 does; the following terms areequivalent:RBL = AISRCL = LOSRLOS = LOFRYEL = RAI49 of 242