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DS21Q55

 

T1 ALARM CRITERIA Table 10-1

 

 

 

 

 

 

 

 

ALARM

SET CRITERIA

CLEAR CRITERIA

 

Blue Alarm (AIS) (Note 1)

Over a 3ms window, five or fewer

Over a 3ms window, six or more zeros are

 

 

 

zeros are received

received

 

 

Yellow Alarm (RAI)

 

 

 

 

D4 Bit-2 Mode (T1RCR2.0 = 0)

Bit 2 of 256 consecutive channels

Bit 2 of 256 consecutive channels is set to

 

 

 

is set to zero for at least 254

zero for less than 254 occurrences

 

 

 

occurrences

 

 

 

D4 12th F -bit Mode (T1RCR2.0 = 1;

12th framing bit is set to one for

12th framing bit is set to zero for two

 

 

this mode is also referred to as the

two consecutive occurrences

consecutive occurrences

 

 

“Japanese Yellow Alarm”)

 

 

 

 

ESF Mode

16 consecutive patterns of 00FF

14 or fewer patterns of 00FF hex out of 16

 

 

 

appear in the FDL

possible appear in the FDL

 

 

Red Alarm (LRCL) (Also referred to

192 consecutive zeros are

14 or more ones out of 112 possible bit

 

 

as Loss Of Signal)

received

positions are received, starting with the

 

 

 

 

first one received

 

NOTES:

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 criteria in the DS21Q55 has been set to achieve this performance. It is recommended that the RBL bit be qua lified with the RLOS bit.

2)ANSI specifications use a different nomenclature than this data sheet does; the following terms are

equivalent:

RBL = AIS

RCL = LOS

RLOS = LOF

RYEL = RAI

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Please contact telecom.support@dalsemi.com or search http://www.maxim-ic.com for updated

information.

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Maxim DS21Q55 specifications T1 Alarm Criteria Table, Alarm SET Criteria Clear Criteria, Yellow Alarm RAI