DS2154
AUTOMATIC ALARM GENERATION
When either CCR2.4 or CCR2.5 is set to 1, the DS2154 monitors the receive side to determine if any of
the following conditions are present: loss of receive frame synchronization, AIS alarm (all 1s) reception,
or loss of receive carrier (or signal). If any one (or more) of the above conditions is present, then the
DS2154 will either force an AIS alarm (if CCR2.5=1) or a Remote Alarm (CCR2.4=1) to be transmitted
via the TPOSO and TNEGO pins. It is an illegal state to have both CCR2.4 and CCR2.5 set to 1 at the
same time. If CCR2.4=1, then RAI will be transmitted according to ETS 300 011 specifications and a
constant Remote Alarm will be transmitted if the DS2154 cannot find CRC4 multiframe synchronization
within 400 ms as per G.706.
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DALLAS [ DALLAS SEMICONDUCTOR ]
