XRT84L38IB Exar Corporation, XRT84L38IB Datasheet - Page 224

• Manufacturer Part Number: XRT84L38IB
• Description: Network Controller & Processor ICs 8 Ch T1/E1 Framer
• Manufacturer: Exar Corporation

Specifications of XRT84L38IB

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

XRT84L38
OCTAL T1/E1/J1 FRAMER
The following table illustrates how payload bits and signaling bits are multiplexed together into the 16.384Mbit/
s data stream.
THIRTEENTH OCTET OF 16.384MBIT/S DATA STREAM
FOURTEENTH OCTET OF 16.384MBIT/S DATA STREAM
FIFTEENTH OCTET OF 16.384MBIT/S DATA STREAM
SIXTEENTH OCTET OF 16.384MBIT/S DATA STREAM
X
A
The Transmit Single-frame Synchronization signal of Channel 0 pulses HIGH for one clock cycle at the first bit
position (F-bit of channel 0) of the data stream with data from Channel 0-3 multiplexed together. The Transmit
Single-frame Synchronization signal of Channel 4 pulses HIGH for one clock cycle at the first bit position (F-bit of
Channel 4) of the data stream with data from Channel 4-7 multiplexed together. By sampling the HIGH pulse on
the Transmit Single-frame Synchronization signal, the framer can position the beginning of the multiplexed DS1
frame. It is responsibility of the Terminal Equipment to align the multiplexed transmit serial data with the Transmit
Single-frame Synchronization pulse.
4. The local Terminal Equipment also multiplexed signaling bits with payload bits and sent them together
5. After payload bits of Timeslot 0, 1 and 2 of all four channels are sent, the Terminal Equipment should stuff
6. Following the same rules of Step 2 to 5, the local Terminal Equipment stuffs eight octets of "don't care" data
Y
Y
: The signaling bit A of Channel Y
: The Xth payload bit of Channel Y
through the 16.384Mbit/s data stream. When the Terminal Equipment is sending the fifth payload bit of a
particular channel, instead of sending it twice, it inserts the signaling bit A of that particular channel. Simi-
larly, the sixth payload bit of a particular channels is followed by the signaling bit B of that channel; the sev-
enth payload bit is followed by the signaling bit C; the eighth payload bit is followed by the signaling bit D.
another eight octets (sixty-four bits) of "don't care" data into the outgoing data stream.
after sending twenty-four octets of multiplexed payload and signaling data. A 16.384Mbit/s data stream is
thus created.
B
B
B
B
5
6
7
8
IT
IT
IT
IT
0
0
0
0
0
0
0
0
B
B
B
B
A
B
C
D
IT
IT
IT
IT
0
0
0
0
1
1
1
1
B
B
B
B
5
6
7
8
IT
IT
IT
IT
1
1
1
1
2
2
2
2
B
B
B
B
A
B
C
D
IT
IT
IT
IT
1
1
1
1
3
3
3
3
204
B
B
B
B
5
6
7
8
IT
IT
IT
IT
2
2
2
2
4
4
4
4
B
B
B
B
C
D
A
B
IT
IT
IT
IT
2
2
2
2
5
5
5
5
B
B
B
B
5
6
7
8
IT
IT
IT
IT
3
3
3
3
6
6
6
6
REV. 1.0.1
B
B
B
B
C
D
A
B
IT
IT
IT
IT
3
3
3
3
7
7
7
7