XRT86L30
REV. 1.0.1
SINGLE T1/E1/J1 FRAMER/LIU COMBO
4.8
T1/E1 Time Slot Substitution and Control
The time slots within PCM data are reserved for carrying individual DS-0’s. However, the framer block
(transmit or receive paths) can substitute the payload with various code definitions. Each time slot can be
independently programmed to carry normal PCM data or a variety of user codes. In E1 mode, the user can
substitute the transmit time slots 0 and 16, although signaling and Frame Sync cannot be maintained. The
following options for time slot substitution are available:
•
•
•
•
•
•
•
•
•
•
•
•
•
F
Unchanged
Invert all bits
Invert even bits
Invert odd bits
Programmable User Code
Busy 0xFF
Vacant 0xD5
Busy TS, Busy 00
A-Law, µ-Law
Invert the MSB bit
Invert all bits except the MSB bit
PRBS
D/E Channel (or Fractional Input)
IGURE 15. T1/E1 TIME
S
LOT
S
UBSTITUTION AND
C
ONTROL
TSn - TSn+m
Substitution
TxSER
F
PCM Data
PCM Data
TxSERclk
TxSYNC
TxMSYNC
150
EXAR [ EXAR CORPORATION ]
