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IDT82V2048 OCTAL T1/E1 SHORT HAUL LINE INTERFACE UNIT
INDUSTRIAL TEMPERATURE RANGES
Figure-20 TAOS with Digital Loopback
Figure-21 TAOS with Analog Loopback
2.17.6 INBAND LOOPBACK
Inband Loopback is a function that facilitates the system remote
diagnosis. When this function is enabled, the chip will detect or generate
the Inband Loopback Code. There are two kinds of Inband Loopback
Code: Activate Code and Deactivate Code. If the Activate Code is
received from the far end in a continuous 5.1 second, the chip will auto-
matically go into Remote Loopback Mode (shown in
Figure-17). If the
Deactivate Code is received from the far end in a continuous 5.1
second, the chip quits from the Remote Loopback mode. The chip can
send the Activate Code and Deactivate Code to the far end. Two func-
tion blocks: IBLC Detector (Inband Loopback Code Detector) and IBLC
Generator (Inband Loopback Code Generator), realize the Inband Loop-
back.
The detection of Inband Loopback Code is enabled by bit LBDE in
register e-LBCF. If bit ALBE in register e-LBCF is set to ‘1’, the chip will
automatically go into or quit from the Remote Loopback mode based on
the receipt of Inband Loopback Code. The length of the Activate Code is
defined in bits LBAL[1:0] in register e-LBCF; and the length of the Deac-
tivate Code is defined in bits LBDL[1:0] in register e-LBCF. The pattern
of the Activate Code is defined in register e-LBAC, and the pattern of
the Deactivate Code is defined in register e-LBDC. The above settings
are globally effective for all the eight channels. The presence of Inband
Loopback Code in each channel is reflected timely in register e-LBS.
Any transition of each bit in register e-LBS will be reflected in register e-
LBI, and if enabled in register e-LBM, will generate an interrupt. The
required sequence of programming the Inband Loopback Code detec-
tion is: First, set registers e-LBAC and e-LBDC, followed by register e-
LBM. Finally, to activate Inband Loopback detection, set register e-
LBCF.
The Inband Loopback Code Generator use the same registers as the
Inband Loopback Detector to define the length and pattern of Activate
Code and Deactivate Code. The length and pattern of the generated
Activate Code and Deactivate Code can be different from the detected
Activate Code and Deactivate Code. Register e-LBGS determines
sending Activate Code or Deactivate Code, and register e-LBGE acts as
a switch to start or stop the sending of Inband Loopback Code to the
selected channels. Before sending Inband Loopback Code, users
should be sure that registers e-LBCF, e-LBAC, e-LBDC and e-LBSG
Jitter
Attenuator
Jitter
Attenuator
B8ZS/
HDB3/AMI
Decoder
B8ZS/
HDB3/AMI
Encoder
Slicer
Peak
Detector
CLK&Data
Recovery
(DPLL)
Line
Driver
Waveform
Shaper
LOS
Detector
One of Eight Identical Channels
RTIPn
RRINGn
TTIPn
TRINGn
LOSn
RCLKn
RDn/RDPn
CVn/RDNn
TCLKn
BPVIn/TDNn
TDn/TDPn
Transmit
All Ones
Jitter
Attenuator
B8ZS/
HDB3/AMI
Decoder
B8ZS/
HDB3/AMI
Encoder
Slicer
Peak
Detector
CLK&Data
Recovery
(DPLL)
Line
Driver
Waveform
Shaper
LOS
Detector
One of Eight Identical Channels
RTIPn
RRINGn
TTIPn
TRINGn
LOSn
RCLKn
RDn/RDPn
CVn/RDNn
TCLKn
BPVIn/TDNn
TDn/TDPn
Transmit
All Ones