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DS3/E3 FRAMER IC
XRT7250
REV. 1.1.1
101
NOTE: For more information on the A-bit, within the ITU-T
G.751 frame, please see Section 4.1.1.1.
Bits 4, 3, TxNSourceSel[1:0]
These two Read/Write bit-fields combine to specify
the source of the N-bit, within each outbound E3
frame. The relationship between these two bit-fields
and the resulting source of the N Bit is tabulated be-
low.
NOTE: For more information on the N-bit, within the ITU-T
G.751 frame, please see Section 4.1.1.2.
Bit 2 - TxAIS Enable
This Read/Write bit-field permits the user to configure
the Transmit Section of the Framer IC to transmit an
AIS pattern to the remote terminal
Setting this bit-field to "0" configures the Transmit
Section (of the chip) to transmit data in a normal man-
ner (e.g., as received via the Input Interface).
Setting this bit-field to "1" configures the Transmit
Section (of the chip) to transmit an "All Ones" pattern
(e.g., an AIS pattern) to the remote terminal.
NOTE: For more information on the AIS pattern, please see
Section 4.2.4.2.1.1.
Bit 1 - TxLOS Enable
This Read/Write bit-field permits the user to configure
the Transmit Section of the Framer IC to transmit an
LOS (e.g., All Zeros) pattern to the remote terminal
Setting this bit-field to "0" configures the Transmit
Section (of the chip) to transmit data in a normal man-
ner (e.g., as received via the Input Interface).
Setting this bit-field to "1" configures the Transmit
Section (of the chip) to transmit an "All Zeros" pattern
(e.g., an LOS pattern) to the remote terminal.
NOTE: For more information on the LOS pattern, please
see Section 4.2.4.2.1.2.
Bit 0 - TxFAS Source Select
This Read/Write bit-field permits the user to configure
the Transmit Section of the Framer IC to either:
a. Internally generate the FAS (Framing Alignment
Signal) pattern, within the outbound E3 frames,
or to
b. use the Input Interface as the source for the FAS
pattern.
Setting this bit-field to "0" configures the Transmit
Section of the Framer IC to internally generate the
FAS pattern, for each outbound E3 frame.
Setting this bit-field to "1" configures the Transmit
Section of the Framer IC to use the Input Interface as
the source for the FAS pattern.
NOTE: For more information on the FAS pattern, please see
Section 4.1.
2.3.7.2
Transmit E3 LAPD Configuration Reg-
ister (ITU-T G.751)
11
Functions as a FEBE (Far-End-Block Error) bit-field.
This bit-field is set to "0", if the Near-End Receive Section (within this chip) detects no BIP-4
Errors within the incoming E3 frames.
This bit-field is set to "1", if the Near-End Receive Section (within this chip) detects a BIP-4
Error within the incoming E3 frame.
TXASOURCESEL[1:0]
SOURCE OF A BIT
TXNSOURCESEL[1:0]
SOURCE OF N BIT
00
TxE3 Service Bits Register (Address = 0x35)
01
Transmit Overhead Data Input Interface
10
Transmit LAPD Controller
11
Transmit Payload Data Input Interface.