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PRELIMINARY
XRT79L71
508
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 upon software control to the remote terminal equipment. The user can accomplish this by
executing the following two-step procedure.
STEP 1 - Write the value "0x40" into the Transmit E3 MA Byte Register, as depicted below.
STEP 2 - Configure the Transmit DS3/E3 Framer block to use the Transmit E3 MA Byte Register as the
source of content for the MA byte, within each outbound E3 frame.
This is accomplished by setting Bit 0 (Transmit MA Byte based upon Receive Conditions), within the Transmit
E3 Configuration Register to "0" as depicted below.
Once the user executes these two steps, then the Transmit DS3/E3 Framer block will begin to read out the
contents of the Transmit E3 MA Byte Register, and will be writing this particular value into the MA Byte, within
each outbound E3 frame. Bit 6, within the Transmit MA Byte Register, corresponds to Bit 2 (FEBE/REI) within
the MA byte. Therefore, by setting Bit 6 (within the Transmit E3 MA Byte Register to "1" the Transmit DS3/E3
Framer block will set the FEBE/REI bit-field within the MA byte-field of each outbound E3 frame to "1". This will
result in the transmission of the FEBE/REI indicator to the remote terminal equipment.
NOTE: In this configuration, the value of the FEBE/REI 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.
6.2.6.4.2
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 EM byte errors.
The user can configure the Transmit DS3/E3 Framer block to automatically transmit the FEBE/REI indicator to
the remote terminal equipment, by setting Bit 0 (Transmit MA Byte based upon Receive Conditions) to "1" as
depicted below.
Transmit E3 MA Byte Register - G.832 (Direct Address = 0x1136)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
TxMA Byte[7:0]
R/W
0
1
0
Transmit E3 Configuration Register - G.832 (Direct Address = 0x1130)
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
Unused
TxDL in NR
Reserved
TxAIS
Enable
TxLOS
Enable
Transmit MA
Byte based
upon
Receive
Conditions
R/O
R/W
R/O
R/W
0