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PRELIMINARY
XRT79L71
142
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
NOTE: Bits 2 through 0 are only active if Bit 7 (Tx FERF Indicator), within the Transmit DS3 Configuration register is set to
"0".
In summary, the XRT79L71 can be configured to transmit the FERF indicator to the remote terminal equipment
anytime its Receive DS3/E3 Framer block detects either an LOS, OOF/LOF or AIS defect condition in the DS3
data that it is receiving from the remote terminal equipment. In the case of DS3 applications, the Transmit
DS3/E3 Framer block will transmit the FERF indicator to the remote terminal by setting each of the X bits within
each outbound DS3 frame to "0".
Conversely, if the Receive DS3/E3 Framer block within the XRT79L71 does not declare either an LOS, OOF or
AIS defect condition, then the corresponding Transmit DS3/E3 Framer block will respond by NOT sending the
FERF indicator to the remote terminal equipment. In this case, the Transmit DS3/E3 Framer block will NOT
transmit the FERF indicator, by setting the X bits within each DS3 frame to "1".
Figure 59 illustrates the Near-End Receive DS3/E3 Framer block within the XRT79L71 declaring the LOS
defect condition within the DS3 data-stream that it is receiving from the remote terminal equpment. Figure 60 illustrates the subsequent action of the corresponding Near-End Transmit DS3/E3 Framer block. In this case,
the Transmit DS3/E3 Framer block will set each of the X bits, within the outbound DS3 frame which is destined
for the remote terminal to "0".
1
TxFERF upon OOF
Defect
R/W
Automatic Transmission of FERF upon OOF Defect:This bit-field per-
mits the user to configure the Transmit DS3/E3 Framer block to auto-
matically transmit the FERF indicator to the remote terminal, upon the
Receive DS3/E3 Framer block declaring the OOF/LOF defect condi-
tion. If this feature is enabled, then the Transmit DS3/E3 Framer block
will transmit the FERF indicator to the remote terminal for the duration
that the companion Receive DS3/E3 Framer block is declaring the
OOF defect condition. The Transmit DS3/E3 Framer block will cease
to transmit the FERF indicator once the Receive DS3/E3 Framer block
has cleared the OOF defect condition.0 - Disables the Automatic
Transmission of FERF upon declaration of the OOF defect feature.1 -
Enables the Automatic Transmission of FERF upon declaration of the
OOF defect feature.
0
TxFERF upon AIS
Defect
R/W
Automatic Transmission of FERF upon AIS Defect:This bit-field permits
the user to configure the Transmit DS3/E3 Framer block to automati-
cally transmit the FERF indicator to the remote terminal, upon the
Receive DS3/E3 Framer block declaring the AIS defect condition. If
this feature is enabled, then the Transmit DS3/E3 Framer block will
transmit the FERF indicator to the remote terminal for the duration that
the companion Receive DS3/E3 Framer block is declaring the AIS
defect condition. The Transmit DS3/E3 Framer block will cease to
transmit the FERF indicator once the Receive DS3/E3 Framer block
has cleared the AIS defect condition.0 - Disables the Automatic Trans-
mission of FERF upon declaration of the AIS defect feature.1 - Enables
the Automatic Transmission of FERF upon declaration of the AIS
defect feature.