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XRT79L71
PRELIMINARY
323
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
REV. P2.0.0
The user can configure the Transmit DS3/E3 Framer block to transmit an LOS pattern by transmitting an "All
Zeros" pattern. The user can accomplish this by setting Bit 1 (Tx LOS Enable), within the "Transmit E3
Configuration Register - G.751" to "1" as depicted below.
Once this step is executed, then the Transmit DS3/E3 Framer block will override all of the outbound E3 data
(payload and overhead bits), with an "All Zeros" Pattern.
5.2.4.2
TRANSMITTING THE E3 AIS PATTERN
The Transmit DS3/E3 Framer block permits the user to (upon Software Control) transmit the E3 AIS indicator
(which is an "Unframed All Ones" Pattern) to the remote terminal equipment. The user can invoke this feature
by setting Bit 2 (TxAIS Enable) within the "Transmit E3 Configuration" Register, to "1" as depicted below.
Once this step is executed, then the Transmit DS3/E3 Framer block will override the contents of all "outbound"
E3 data, with this E3 AIS (e.g., an "Unframed, All Ones") Pattern.
5.2.4.3
TRANSMITTING THE FERF/RDI INDICATOR
The Transmit E3 Framer block can be configured to transmit the FERF/RDI indicator to the remote terminal,
under software control, provided that it (the Transmit E3 Framer block) is not also configured to compute and
insert the BIP-4 value into each "outbound" E3 frame.
More specifically, the following items must be noted about the Transmit E3 Framer blocks, when it comes to
generating the FERF/RDI indicator (while operating in the ITU-T G.751 Framing format).
1.
The Transmit E3 Framer block CANNOT be configured to automatically generate the FERF/RDI
indicator, in response to a "Service-Affecting" defect condition being declared by the corresponding
Receive E3 Framer block (This is in contrast to the E3, ITU-T G.832 and the two DS3 framing formats).
2.
The Transmit E3 Framer block CAN ONLY be configured to generate the FERF/RDI indicator, upon
Software Control (provided that it is NOT configured to compute and insert the BIP-4 value within each
outbound E3 frame)
3.
If the Transmit E3 Framer block is configured to compute and insert the BIP-4 value into each outbound
E3 frame, then it will NOT be able to transmit the FERF/RDI indicator. (In this case, the "A" bit will take
Forced Transmission of the FERF/RDI Indicator
The XRT79L71 permits the user to force the Transmit E3 Framer block to transmit the FERF/RDI indicator to
the remote terminal equipment. The user can accomplish this by executing the following steps.
Transmit E3 Configuration Register - G.751 (Address = 0x1130)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxBIP-4
Enable
TxASrcSel[1:0]
TxNSrcSel[1:0]
TxAIS
Enable
TxLOS
Enable
TxFAS
Source Sel
R/W
0
1
0
Transmit E3 Configuration Register - G.751 (Address = 0x1130)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxBIP-4
Enable
TxASrcSel[1:0]
TxNSrcSel[1:0]
TxAIS
Enable
TxLOS
Enable
TxFAS
Source Sel
R/W
0
1
0