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PRELIMINARY
XRT79L71
328
REV. P2.0.0
1-CHANNEL DS3/E3 CLEAR-CHANNEL FRAMERLIU COMBO - CC/HDLC ARCHITECTURE
The XRT79L71 permits the user to force the Transmit DS3/E3 Framer block to force the transmission of the
FEBE/REI indicator, via the "A" bit (upon Software Control) to the remote terminal equipment. The user can
accomplish this by executing the following two-step procedure.
STEP 1 - Set Bit 1 (TxA), within the "Transmit E3 Service Bits" Register to "1" as depicted below.
STEP 2 - Set Bits 5 and 6 (TxASrcSel[1:0]), within the "Transmit E3 Configuration" Register, to "[0, 0]"
as depicted below.
Once these two steps are executed, then the Transmit DS3/E3 Framer block will begin to read out the contents
of "Bit 1" (TxA), within the "Transmit E3 Service Bits" Register, and it will be setting the "A" bit (within each
outbound E3 frame) to this particular value. This action will result in the transmission of the "FEBE/REI"
indicator being transmitted to the remote terminal equipment.
NOTE: In this configuration, the value of the "A" bit-field, that is being generated by the Transmit DS3/E3 Framer block does
not reflect the health of the E3 signal that is being received by the corresponding "Near-End" Receive DS3/E3
Framer block.
5.2.4.4.2
Automatic Transmission of the FEBE/REI Indicator
The XRT79L71 permits the user to configure the Transmit E3 Framer block to automatically transmit the FEBE/
REI indicator, in response to whenever the Receive DS3/E3 Framer block detects BIP-4 nibble errors.
Configure the Transmit DS3/E3 Framer block to automatically transmit the FEBE/REI indicator to the remote
terminal equipment (via the A bit) by executing the following two steps.
STEP 1 - Set Bit 0 (RxBIP-4 Enable), within the "Receive E3 Configuration and Status Register # 1 -
G.751" to "1" as depicted below.
STEP 2 - Set Bit 7 (TxBIP-4 Enable), within the "Transmit E3 Configuration" Register to "1" as depicted
below.
Transmit E3 Service Bits Register - G.751 (Address = 0x1135)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
TxA
TxN
R/O
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
Receive E3 Configuration and Status Register # 1 - G.751 (Address = 0x1110)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
RxFERFAlgo
Unused
RxBIP-4
Enable
R/O
R/W
R/O
R/W
0
1