XRT84L38IB Exar Corporation, XRT84L38IB Datasheet - Page 232

• 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
SIXTEENTH OCTET OF 16.384MBIT/S DATA STREAM
X
A
The Transmit Single-frame Synchronization signal should pulse HIGH for two clock cycles (the last bit position of
the previous multiplexed frame and the first bit position of the next multiplexed frame) indicating frame boundary
of the multiplexed data stream. The Transmit Single-frame Synchronization signal of Channel 0 pulses HIGH to
identify the start of multiplexed data stream of Channel 0-3. The Transmit Single-frame Synchronization signal of
Channel 4 pulses HIGH to identify the start of multiplexed data stream of Channel 4-7. 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.
Inside the framer, all the "don't care" bits will be stripped away. The framing bits, signaling and payload data are
de-multiplexed inside the XRT84L38 and send to each individual channel. These data will be processed by each
individual framer and send to LIU interface. The local Terminal Equipment provides a free-running 1.544MHz
clock to the Transmit Serial Input clock of each channel. The framer will use this clock to carry the processed
payload and signaling data to the transmit section of the device.
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
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
5
IT
3
0
B
A
IT
3
1
B
6
IT
3
2
B
B
IT
3
3
212
B
7
IT
3
4
B
C
IT
3
5
B
8
IT
3
6
REV. 1.0.1
B
D
IT
3
7