xrt94l33 Exar Corporation, xrt94l33 Datasheet - Page 311

• Manufacturer Part Number: xrt94l33
• Description: Multi-channel, Multi-function Device Aggregates 3 Ds3/e3/sts-1 Into Oc3/stm-1
• Manufacturer: Exar Corporation

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3-CHANNEL DS3/E3/STS-1 TO STS-3/STM-1 MAPPER IC DATA SHEET
Figure 62 Illustration of the “Near-End” Receive STS-3 TOH Processor block receiving a STS-3 frame
(from the remote LTE) with the correct B2 byte value
Figure 63 Illustration of the “Near-End” Transmit STS-3 TOH Processor block transmitting an STS-3
frame (to the remote LTE) with the REI-L value set to “0”
Conversely, if the “Near-End” Receive STS-3 TOH Processor block detects an error in the incoming B2 byte,
then it will notify the remote LTE of this fact, by having the “Near-End” Transmit STS-3 TOH Processor block
set the “REI-L” bits, within the “outbound” STS-3 frame (which is destined for the remote LTE) to the value,
reflecting the total number of bit-errors that have been detected within the B2 byte.
Figure 64 illustrates the “Near-End” Receive STS-3 TOH Processor block receiving an erred STS-3 frame
from the remote LTE. In this figure, the “Near-End” Receive STS-3 TOH Processor block is receiving an
STS-3 frame, with a B2 byte value of “0x5F”. This value does not match the “locally computed” B2 byte value
of “0x5A”. Consequently, there is an error in the Line Overhead and STS-3c Envelope Capacity bytes, within
this STS-3 frame. Now, since this B2-byte mismatch is due to two bits being in error, the REI-L bits will be set
to the value “2”.
Locally Computed B2 Byte = 0x5A
Near-End LTE
Near-End LTE
STS-1 TOH
STS-1 TOH
STS-1 TOH
STS-1 TOH
Processor
Processor
Transmit
STS-1 TOH
STS-1 TOH
Processor
Processor
Transmit
Receive
STS-1 TOH
STS-1 TOH
Receive
Processor
Processor
Block
Block
Transmit
Processor
Processor
Block
Block
Transmit
Receive
Receive
Block
Block
Block
Block
Outbound STS-1 Frame
Incoming STS-1 Frame
0x00
311
0x5A
M0 Byte
B2 Byte
Remote
Remote
Remote
LTE
Remote
LTE
LTE
LTE
XRT94L33
Rev.1.2.0.