
DS26518 8-Port T1/E1/J1 Transceiver 
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Table 9-41. T1.231, G.775, and ETS 300 233 Loss Criteria Specifications 
STANDARD 
ITU-T G.775 
CRITERIA 
T1.231 
ETS 300 233 
Loss 
Detection 
No pulses are detected for 175 
±75 bits. 
No pulses are detected for 
duration of 10 to 255 bit 
periods. 
The incoming signal has 
transitions for duration of 10 to 
255 bit periods. 
No pulses are detected for a 
duration of 2048 bit periods or 
1ms. 
Loss reset criteria is not 
defined. 
Loss Reset  
Loss is terminated if a duration 
of 12.5% ones are detected 
over duration of 175 ±75 bits. 
Loss is not terminated if 8 
consecutive zeros are found if 
B8ZS encoding is used. If 
B8ZS is not used, loss is not 
terminated if 100 consecutive 
pulses are zero. 
9.12.3.6 
ANSI T1.231 for T1 and J1 Modes 
For short-haul mode, loss is declared if the received signal level is 3dB lower from the programmed value (based 
on 
Table 10-20
) for a duration of 192-bit periods. Hence, if the sensitivity is programmed to be 12dB, loss is 
declared at 15dB. 
LOS is reset if all the following crieria are met: 
1) 24 or more ones are detected in a 192-bit period with a programmed sensitivity level measured at RTIPn 
and RRINGn. 
2) During the 192 bits, fewer than 100 consecutive zeros are detected. 
For long-haul mode, loss is detected if the received signal level is 3dB lower from the programmed value (based on 
Table 10-20
) for a duration of 192-bit periods. Hence, if the sensitivity is programmed to be 30dB, the loss 
declaration level is 33dB. 
LOS is reset if all the following crieria are met: 
1) 24 or more ones are detected in a 192-bit period with a programmed sensitivity level measured at RTIPn 
and RRINGn. 
2) During the 192 bits, fewer than 100 consecutive zeros are detected. 
9.12.3.7 
ITU-T G.775 for E1 Modes 
For short-haul mode, loss is declared if the received signal level is 3dB lower from the programmed value (based 
on 
Table 10-20
) for a duration of 192-bit periods. Hence, if the sensitivity is programmed to be 12dB, loss is 
declared at 15dB. LOS is reset if the receive signal level is greater than or equal to the programmed sensitivity 
level for a duration of 192-bit periods. 
For long-haul mode, loss is detected if the received signal level is 3dB lower from the programmed value (based on 
Table 10-20
) for a duration of 192-bit periods. Hence, if the sensitivity is programmed to be 30dB, the loss 
declaration level is 15dB. LOS is reset if the receive signal level is greater than or equal to the programmed 
sensitivity level for a duration of 192-bit periods. 
9.12.3.8 
ETS 200 233 for E1 Modes 
For short-haul mode, loss is declared if the received signal level is 3dB lower from the programmed value (based 
on 
Table 10-20
) continusou duration of 2048-bit periods (1ms). LOS is reset if the receive signal level is greater 
than or equal to the programmed sensitivity level for a duration of 192-bit periods. 
For long-haul mode, loss is declared if the received signal level is 3dB lower from the programmed value (based on 
Table 10-20
) continuous duration of 2048-bit periods (1ms). LOS is reset if the receive signal level is greater than 
or equal to the programmed sensitivity level for a duration of 192-bit periods.