XRT72L50 Datasheet, PDF (97/471 Pages) Exar Corporation – SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER

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XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER WITH HDLC CONTROLLER
REV. 1.2.1
Bit 5 - Tx Idle (Pattern)
This Read/Write bit-field permits the user to command the Transmit DS3/E3 Framer block to transmit the Idle
Condition pattern. If the user invokes this command, then the Transmit DS3/E3 Framer block will force the
outbound DS3 Frames to have the following patterns.
• Valid M-bits, F-bits and P-bits
• The three CP-Bits (F-frame #3) are "0"
• The X-bits are set to "1"
• A repeating "1100..." pattern in written into the payload portion of the DS3 Frames.
Writing a "1" to this bit-field invokes this command. Writing a "0" allows the Transmit DS3/E3 Framer block to
function normally (e.g., the Transmit DS3/E3 Framer block will transmit its payload and internally generated
overhead bits).
NOTE: For more information on this feature, refer to Section 4.2.4.2.1.3.
NOTE: This bit-setting is ignored if Bits 3 or 4 (within this register) are set to "1".
Bit 4 - Tx AIS (Pattern)
This Read/Write bit-field permits the user to command the Transmit DS3/E3 Framer block to transmit an AIS
pattern. If the user invokes this command, then the Transmit DS3/E3 Framer block will force the outbound DS3
frames to have the following patterns.
• Valid M-bits, F-bits, and P-bits
• All C-bits are set to '0'
• All X-bits are set to '1'
• A repeating '1010...' pattern is written into the payload of the DS3 Frames.
Writing a "1' to this bit-field invokes this command. Writing a "0" allows the Transmit DS3/E3 Framer block to
function normally (e.g., the Transmit DS3/E3 Framer block will transmit its payload and internally generated
overhead bits).
NOTE: For more information on this feature, refer to Section 4.2.4.2.1.4.
Bit 3 - Tx LOS (Loss of Signal)
This Read/Write bit-field permits the user to command the Transmit DS3/E3 Framer block to simulate an LOS
Condition. If the user invokes this command, then the Transmit DS3/E3 Framer block will stop sending mark
pulses out on the line and will transmit an all-zero pattern.
Writing a '0' to this bit-field disables (or shuts off) this feature, thereby allowing internally generated DS3
Frames to be generated and transmitted over the line.
Writing a '1' to this bit-field invokes this command, causing the Transmit DS3/E3 Framer block to generate an
all '0' pattern.
NOTE: For more information on this feature, refer to Section 4.2.4.2.1.5.
Bit 2 - FERF on LOS
This Read/Write bit-field allows the user to configure the Transmit DS3/E3 Framer block to generate a Yellow
Alarm if the Near-End Receive DS3/E3 Framer block (within the same channel) detects a LOS (Loss of Signal)
Condition.
Writing a "1" to this bit-field enables this feature. Writing a "0" to this bit-field disables this feature.
NOTE: For more information on this feature, refer to Section 4.2.4.2.1.6.
Bit 1 - FERF on OOF
This Read/Write bit-field allows the user to configure the Transmit DS3/E3 Framer block to generate a Yellow
Alarm if the Near-End Receive DS3/E3 Framer block (within the same channel) detects an OOF (Out-of-
Frame) Condition.
Writing a "1" to this bit-field enables this feature. Writing a "0" to this bit-field disables this feature.
NOTE: For more information on this feature, refer to Section 4.2.4.2.1.7.
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