Datasheet

DS26303: 3.3V, T1/E1/J1, Short-Haul, Octal Line Interface Unit
61 of 101
Table 6-6. AIS Criteria T1.231, G.775, and ETS 300 233 Specifications
STANDARD
CRITERIA
ITU-T G.775 FOR E1 ETS 300 233 FOR E1 ANSI T1.231 FOR T1
AIS
Detection
Two or fewer 0s in each of two
consecutive 512-bit streams
received.
Fewer than three 0s detected
in 512-bit period.
Fewer than nine 0s detected
in a 8192-bit period (a ones
density of 99.9% over a period
of 5.3ms) are received.
AIS
Clearance
Three or more 0s in each of two
consecutive 512-bit streams
received.
Three or more 0s in a 512-bit
period received.
Nine or more 0s detected in a
8192-bit period are received.
Table 6-7. AIS Detection and Reset Criteria
STANDARD
CRITERIA
ITU-T G.775 FOR E1 ETS 300 233 FOR E1 ANSI T1.231 FOR T1
AIS
Detection
Two or fewer 0 in each of two
consecutive 512-bit streams
received.
Fewer than three 0s detected
in 512-bit period.
Fewer than nine 0s contained
in 8192 bits.
AIS
Clearance
Three or more 0s in each of two
consecutive 512-bit streams
received.
Three or more 0s in a 512-bit
period received.
Nine or more bits received in a
8192-bit stream.
Table 6-8. Registers Related to AIS Detection
REGISTER NAME FUNCTIONALITY
LOS/AIS Criteria Selection LASCS
Section criteria for AIS. T1.231, G.775, ETSI 300 233 for
E1.
Alarm Indication Signal Status AIS Set when AIS is detected.
AIS Interrupt Enable AISIE If reset interrupt due to AIS is not generated.
AIS Interrupt Status AISIS
Latched if there is a change in AIS and the interrupt is
enabled.