XRT72L13 Datasheet, PDF (285/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

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PRELIMINARY
XRT72L13
M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC
REV. P1.0.6
TABLE 22: THE RELATIONSHIP BETWEEN THE CONTENTS OF BIT 6 (TX X-BITS) WITHIN THE TX DS3 CONFIGURATION
REGISTER, AND THE RESULTING TRANSMIT DS3 FRAMER BLOCK'S ACTION
BIT 6
0
1
TRANSMIT DS3 FRAMER'S ACTION
Normal Operation:
The X-bits are generated by the Transmit DS3 Framer block based upon "Receiving Conditions" (as detected
by the Receive Section of the Framer chip).
Set X-bits to "1":
The Transmit DS3 Framer will overwrite the X-bits by setting them to "1". Payload information is not modified
and is transmitted as normal.
NOTE: This bit is ignored when either the Transmit Yellow
Alarm, Tx AIS, Tx IDLE, or TxLOS bit is set.
4.2.4.2.1.3 Transmit Idle Pattern - Bit 5
This "read/write" bit field permits the user to transmit
an "Idle pattern" to the "remote terminal equipment"
upon software control. Table 23 relates the contents
of this bit field to the Transmit DS3 Framer's action.
TABLE 23: 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 24 relates the contents
of this bit field to the Transmit DS3 Framer block's ac-
tion.
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