XRT72L50 Datasheet, PDF (187/471 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
TABLE 26: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 5 (TX IDLE) WITHIN THE TX DS3 CONFIGURATION
REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER ACTION
BIT 5
TRANSMIT DS3 FRAMER'S ACTION
0 _{Normal Operation:}
The Overhead bits are either internally generated, or they are inserted via the Transmit Overhead Data Input
Interface or the Transmit HDLC Controller blocks. The Payload bits are received from the Transmit Payload Data
Input Interface.
1 _{Transmit Idle Condition Pattern:}
When this command is invoked, the Transmit DS3 Framer will do the following:
• Set the X-bits to 1
• Set the CP-Bits (F-Frame #3) to 0
• Generate Valid M, F, and P bits
Overwrite the data in the DS3 payload with a repeating 1100... pattern.
NOTE: This bit is ignored when either the Tx AIS or the Tx LOS bit is set.
4.2.4.2.1.4
Transmit AIS Pattern - Bit 4
This read/write bit field allows the user to transmit an AIS pattern to the remote terminal equipment, upon
software control. Table 27 relates the contents of this bit field to the Transmit DS3 Framer block's action.
TABLE 27: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 4 (TX AIS PATTERN) WITHIN THE TX DS3
CONFIGURATION REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER BLOCK'S ACTION
BIT 4
TRANSMIT DS3 FRAMER'S ACTION
0 _{Normal Operation:}
The Overhead bits are either internally generated, or they are inserted via the Transmit Overhead Data Input
Interface or the Transmit HDLC Controller blocks. The Payload bits are received from the Transmit Payload Data
Input Interface.
1 _{Transmit AIS Pattern:}
When this command is invoked, the Transmit DS3 Framer block will do the following.
• Set the X-bits to 1
• Set all the C-bits to 0
• Generate valid M, F, and P bits
Overwrite the data in the DS3 payload with a repeating 1010... pattern
NOTE: This bit is ignored when the TxLOS bit is set.
4.2.4.2.1.5
Transmit LOS Pattern - Bit 3
This read/write bit field allows the user to transmit an LOS (Loss of Signal) pattern to the remote terminal, upon
software control. Table 28 relates the contents of this bit field to the Transmit DS3 Framer block's action.
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