Rainbow Electronics DS2152 - Manual (Page 29)

DS2152
031897 29/79
ALARM CRITERIA Table 4–2
ALARM SET CRITERIA CLEAR CRITERIA
Blue Alarm (AIS)
(see note 1 below) when over a 3 ms window,
5 or less zeros are received when over a 3 ms window,
6 or more zeros are received
Yellow Alarm (RAI)
1. D4 bit 2 mode(RCR2.2=0)
2. D4 12th F–bit mode
(RCR2.2=1; this mode is also
referred to as the “Japanese
Yellow Alarm”)
3. ESF mode
when bit 2 of 256 consecutive chan-
nels is set to zero for at least 254
occurrences
when the 12th framing bit is set to
one for two consecutive occur-
rences
when 16 consecutive patterns of
00FF appear in the FDL
when bit 2 of 256 consecutive chan-
nels is set to zero for less than 254
occurrences
when the 12th framing bit is set to
zero for two consecutive occur-
rences
when 14 or less patterns of 00FF
hex out of 16 possible appear in the
FDL
Red Alarm (LRCL)
(this alarm is also referred to as
Loss Of Signal) when 192 consecutive zeros
are received when 14 or more ones out of 112
possible bit positions are received
starting with the first one received
NOTES:
1. The definition of Blue Alarm (or Alarm Indication Sig-
nal) is an unframed all ones signal. Blue alarm
detectors should be able to operate properly in the
presence of a 10–3 error rate and they should not
falsely trigger on a framed all ones signal. The blue
alarm criteria in the DS2152 has been set to achieve
this performance. It is recommended that the RBL
bit be qualified with the RLOS bit.
2. ANSI specifications use a different nomenclature
than the DS2152 does; the following terms are
equivalent:
RBL = AIS
LRCL = LOS
RLOS = LOF
RYEL = RAI
SR2: STATUS REGISTER 2 (Address=21 Hex)
(MSB) (LSB)
RMF TMF SEC RFDL TFDL RMTCH RAF RSC
SYMBOL POSITION NAME AND DESCRIPTION
RMF SR2.7 Receive Multiframe. Set on receive multiframe boundaries.
TMF SR2.6 Transmit Multiframe. Set on transmit multiframe boundaries.
SEC SR2.5 One Second Timer. Set on increments of one second based on RCLK; will
be set in increments of 999 ms, 999 ms, and 1002 ms every 3 seconds.
RFDL SR2.4 Receive FDL Buffer Full. Set when the receive FDL buffer (RFDL) fills to
capacity (8 bits).
TFDL SR2.3 Transmit FDL Buffer Empty. Set when the transmit FDL buffer (TFDL)
empties.
RMTCH SR2.2 Receive FDL Match Occurrence. Set when the RFDL matches either
RFDLM1 or RFDLM2.
RAF SR2.1 Receive FDL Abort. Set when eight consecutive one’s are received in the
FDL.
RSC SR2.0 Receive Signaling Change. Set when the DS2152 detects a change of
state in any of the robbed–bit signaling bits.