XRT72L13 Datasheet, PDF (132/370 Pages) Exar Corporation – M13 MULTIPLEXER/CLEAR CHANNEL DS3 FRAMER IC

XRT72L13 MULTIPLEXER/FRAMER IC
REV. 1.0.6
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PRELIMINARY
This “Read/Write” bit-field permits the user to config-
ure the XRT72L13 to transmit a “DS1 Channel 27 -
Loop-back Request” signal to the Remote Terminal
Equipment. When the Remote Terminal Equipment
receives this request, it is expected to respond by
configuring its own DS1 Channel 27 signal into Loop-
back Mode.
NOTE: This bit-field is ignored if the XRT72L13 has been
configured to operate in the “ITU-T G.747” Mode.
Bit 2 - Loop-back Request - DS1 Channel 26
This “Read/Write” bit-field permits the user to config-
ure the XRT72L13 to transmit a “DS1 Channel 26 -
Loop-back Request” signal to the Remote Terminal
Equipment. When the Remote Terminal Equipment
receives this request, it is expected to respond by
configuring its own DS1 Channel 26 signal into Loop-
back Mode.
NOTE: This bit-field is ignored if the XRT72L13 has been
configured to operate in the “ITU-T G.747” Mode.
Bit 1 - Loop-back Request - DS1 Channel 25
This “Read/Write” bit-field permits the user to config-
ure the XRT72L13 to transmit a “DS1 Channel 25 -
Loop-back Request” signal to the Remote Terminal
Equipment. When the Remote Terminal Equipment
receives this request, it is expected to respond by
configuring its own DS1 Channel 25 signal into Loop-
back Mode.
NOTE: This bit-field is ignored if the XRT72L13 has been
configured to operate in the “ITU-T G.747” Mode.
Bit 0 - Loop-back Request - DS1 Channel 24
This “Read/Write” bit-field permits the user to config-
ure the XRT72L13 to transmit a “DS1 Channel 24 -
Loop-back Request” signal to the Remote Terminal
Equipment. When the Remote Terminal Equipment
receives this request, it is expected to respond by
configuring its own DS1 Channel 24 signal into Loop-
back Mode.
NOTE: This bit-field is ignored if the XRT72L13 has been
configured to operate in the “ITU-T G.747” Mode.
2.3.2.45 Tx DS3 Configuration Register )
TX DS3 CONFIGURATION REGISTER (ADDRESS = 0X30)
BIT 7
Tx Yellow
Alarm
R/W
0
BIT 6
Tx X Bits
R/W
0
BIT 5
Tx Idle
R/W
0
BIT 4
Tx AIS
R/W
0
BIT 3
Tx LOS
R/W
0
BIT 2
FERF on
LOS
R/W
1
BIT 1
FERF on
OOF
R/W
1
BIT 0
FERF on
AIS
R/W
1
Bit 7 - Tx Yellow Alarm
This "Read/Write" bit-field allows the local µP to com-
mand the Transmit DS3 Framer to transmit a "Yellow
Alarm" (e.g., X bits are all "0") in the outgoing DS3
data stream.
Writing a "0" to this bit-field disables this feature (the
default condition). In this condition, the X-bits in the
out-bound DS3 frame, are internally generated
(based upon receiver conditions).
Writing a "1" to this bit-field invokes this command. In
this condition, the Transmit DS3 Framer will override
the internally-generated X-bits and force all of the X-
bits of each outbound DS3 frame to "0".
NOTE: For more information in this feature, please see Sec-
tion _.
NOTE: This bit-setting is ignored if Bits 3, 4 or 5 (within this
register) are set to "1".
Bit 6 - Tx X-Bit (Force X bits to "1")
This "Read/Write" bit-field allows the user to com-
mand the Transmit DS3 Framer to force all of the X-
bits, in the outbound DS3 Frames, to "1".
Writing a "0" to this bit-field disables this feature (the
default condition). In this case, the Transmit DS3
Framer will generate X-bits based upon the receive
conditions.
Writing a "1" to this bit-field invokes this command. In
this case, the Transmit DS3 Framer will overwrite the
internally-generated X-bits and set them all to "1".
NOTE: For more information on this feature, please see
Section _.
NOTE: This bit-setting is ignored if Bits 3, 4, 5, or 7 (within
this register) are set to "1".
Bit 5 - Tx Idle (Pattern)
This "Read/Write" bit-field allows the user to com-
mand the Transmit DS3 Framer to transmit the "Idle
Condition" pattern. If the user invokes this com-
mand, then the Transmit DS3 Framer 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 pay-
load portion of the DS3 Frames.
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