
XRT84L38
203
REV. 1.0.1
Transmit Input Clock (TxInClk_n)
Transmit Time-slot Indication clock (TxTSClk_n)
Transmit Time Slot indicator bits (TxTSb[4:0]_n)
The Transmit Back-plane Interface is accepting data through TxSer_0 or TxSer_4 pins at 16.384Mbit/s. The local
Terminal Equipment multiplexes payload and signaling data of every four channels into one 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.
OCTAL T1/E1/J1 FRAMER
Free-running clocks of 16.384MHz is 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 Interface 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 this 16.384Mbit/s 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.
After the first octet of data is sent, the local Terminal Equipment should insert seven octets (fifty-six bits) of
"don't care" data into the outgoing data stream.
3.
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 16.384Mbit/s data stream.
X
Y
: The Xth payload bit of Channel Y
FIRST OCTET OF 16.384MBIT/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
NINETH OCTET OF 16.384MBIT/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
TENTH OCTET OF 16.384MBIT/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