XRT75R12 Datasheet, PDF (26/89 Pages) Exar Corporation – TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR

XRT75R12
REV. P1.0.2
PRELIMINARY
TWELVE CHANNEL E3/DS3/STS-1 LINE INTERFACE UNIT WITH JITTER ATTENUATOR
3.5.3 E3 LOS Condition:
If the level of incoming line signal drops below the threshold as described in the ITU-T G.775 standard, the
LOS condition is detected. Loss of signal is defined as no transitions for 10 to 255 consecutive zeros. No
transitions is defined as a signal level between 15 and 35 dB below the normal. This is illustrated in Figure 8.
The LOS condition is cleared within 10 to 255 UI after restoration of the incoming line signal. Figure 9 shows
the LOS declaration and clearance conditions.
FIGURE 8. LOSS OF SIGNAL DEFINITION FOR E3 AS PER ITU-T G.775
0 dB
-12 dB
-15dB
LOS Signal Must be Cleared
Maximum Cable Loss for E3
-35dB
LOS Signal may be Cleared or Declared
LOS Signal Must be Declared
FIGURE 9. LOSS OF SIGNAL DEFINITION FOR E3 AS PER ITU-T G.775.
RTIP/
RRing
Actual Occurrence
of LOS Condition
Line Signal
is Restored
10 UI
255 UI
Time Range for
LOS Declaration
10 UI
255 UI
RLOS Output Pin
0 UI
G.775
Compliance
0 UI
Time Range for
LOS Clearance
G.775
Compliance
23