CN8223 Datasheet, PDF (54/161 Pages) Conexant Systems, Inc – ATM Transmitter/Receiver with UTOPIA Interface

2.0 Functional Description
2.4 Status and Alarms
CN8223
ATM Transmitter/Receiver with UTOPIA Interface
2.4.2 Alarm Signal Generation
Three alarm signals can be generated by the transmitter in DS3 mode. These
alarms are generated by setting Transmit Alarm Control [bits 6–4] of the
CONFIG_2 register [0x01]. The yellow alarm is contained in the X1 and X2 bits.
DS3 AIS has the highest priority, followed by idle code, and finally yellow alarm.
DS3 FEBE alarms are generated automatically in the transmitter when the
receiver detects either a frame bit error or a C-parity error in an M-frame. When
no alarm condition is present, the FEBE channel contains all-1s. When an alarm
is to be sent (as determined by the receiver) the FEBE channel is set to all 0s for
one M-frame for each error occurrence.
In G.751 E3 mode, transmission of AIS (unframed all 1s) is enabled by setting
Transmit Alarm Control [bit 4] high. Transmission of yellow alarm is enabled by
setting Transmit Alarm Control [bit 6] high. This causes the transmitted A-bit to
be set to one.
In G.832 E3/E4 modes, transmission of AIS or the MA FERF indication is
enabled by setting Transmit Alarm Control [bits 4 or 5], respectively. The MA
timing marker bit can be set by setting Transmit Alarm Control [bit 6].
In STS-1 and STS-3c/STM-1 modes, transmission of line Alarm Indication
Signal (AIS), Line Far End Receive Failure (FERF), and various path indications
can be enabled as described in Section 3.3.
2-20
Conexant
100046C