
XRT86L30
SINGLE T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.1
PRELIMINARY
219
11.2.3 Multiplexed High-Speed Mode
When the Back-plane interface data rate is 12.352Mbit/s, 16.384Mbit/s, HMVIP 16.384Mbit/s, and H.100
16.384Mbit/s, the interface signals are all configured as inputs, except the receive serial data on RxSER and
the multi frame sync pulse provided by the framer. The Back-plane Interface is processing data through
TxSER0 or TxSER4 pins at 12.352Mbit/s or 16.384Mbit/s. The local Terminal Equipment multiplexes payload
and signaling data of every four channels into one serial data stream. Payload and signaling data of Channel 0-3
are multiplexed onto the Transmit Serial Data pin of Channel 0. Payload and signaling data of Channel 4-7 are
multiplexed onto the Transmit Serial Data pin of Channel 4. Free-running clocks of 12.352MHz are supplied to
the Transmit Input Clock pin of Channel 0 and Channel 4 of the framer. The local Terminal Equipment provides
multiplexed payload data at rising edge of this Transmit Input Clock. The Transmit High-speed Back-plane Inter-
face of the framer then latches incoming serial data at falling edge of the clock. The local Terminal Equipment
maps four 1.544Mbit/s DS1 data streams into one 12.352Mbit/s serial data stream as described below:
1.
The F-bit of four channels are repeated and grouped together to form the first octet of the multiplexed data
stream. The F-bit of Channel 0 is sent first, followed by F-bit of Channel 1 and 2. The F-bit of Channel 3 is
sent last. The table below shows bit-pattern of the first octet.
F
X
: F-bit of Channel X
2.
Payload data of four channels are repeated and grouped together in a bit-interleaved way. The first pay-
load bit of Timeslot 0 of Channel 0 is sent first, followed by the first payload bit of Timeslot 0 of Channel 1
and 2. The first payload bit of Timeslot 0 of Channel 3 is sent last. After the first bits of Timeslot 0 of all four
channels are sent, it comes the second bit of Timeslot 0 of Channel 0 and so on. The table below demon-
strates how payload bits of four channels are mapped into the 12.352Mbit/s data stream.
X
Y
: The Xth payload bit of Channel Y
3.
The local Terminal Equipment also multiplexes signaling bits with payload bits and sends them together
through the 12.352Mbit/s data stream. When the Terminal Equipment is sending the fifth payload bit of
each channel, instead of sending it twice, it inserts the signaling bit A of that corresponding channel. Simi-
larly, the sixth payload bit of a each channel is followed by the signaling bit B of that channel; the seventh
payload bit is followed by the signaling bit C; the eighth payload bit is followed by the signaling bit D.
FIRST OCTET OF 12.352MBIT/S DATA STREAM
B
IT
0
B
IT
1
B
IT
2
B
IT
3
B
IT
4
B
IT
5
B
IT
6
B
IT
7
F
0
F
0
F
1
F
1
F
2
F
2
F
3
F
3
SECOND OCTET OF 12.352MBIT/S DATA STREAM
B
IT
0
B
IT
1
B
IT
2
B
IT
3
B
IT
4
B
IT
5
B
IT
6
B
IT
7
1
0
1
0
1
1
1
1
1
2
1
2
1
3
1
3
THIRD OCTET OF 12.352MBIT/S DATA STREAM
B
IT
0
B
IT
1
B
IT
2
B
IT
3
B
IT
4
B
IT
5
B
IT
6
B
IT
7
2
0
2
0
2
1
2
1
2
2
2
2
2
3
2
3