DS3172N Maxim Integrated, DS3172N Datasheet - Page 86

• Manufacturer Part Number: DS3172N
• Description: Network Controller & Processor ICs Dual DS3/E3 Single Chip Transceiver
• Manufacturer: Maxim Integrated

Specifications of DS3172N

• Part # Aliases: 90-31720-N00

10.6.6 M23 DS3 Framer/Formatter
10.6.6.1 Transmit M23 DS3 Frame Processor
The M23 DS3 frame format is shown in
are the Remote Defect Indication (RDI) bits (also referred to as the far-end SEF/AIS bits). P
bits used for line error monitoring. M
alignment bits. C
tributary #X. The X-bit, P-bit, M-bit, C-bit, and F-bit positions are overhead bits, and the remainder of the bit
positions in the T3 frame are payload bits regardless of how they are marked by TDEN.
Table 10-28. M23 DS3 Frame Overhead Bit Definitions
Bit
X
P
M
F
C
C
10.6.6.2 Transmit M23 DS3 Frame Generation
M23 DS3 frame generation receives the incoming payload data stream, and overwrites all of the DS3 overhead bit
locations.
The multiframe alignment bits (M
respectively.
The subframe alignment bits (F
respectively.
The X-bits (X
programmable (automatic, 1, or 0). If the RDI is generated automatically, the X-bits are set to zero when one or
more of the indicated alarm conditions is present, and set to one when all of the indicated alarm conditions are
absent. Automatically setting RDI on LOS, SEF, LOF, or AIS is individually programmable (on or off).
The P-bits (P
payload parity is calculated by performing modulo 2 addition of all of the payload bits after all frame processing has
been completed. P-bit generation is programmable (on or off). The P-bits will be generated if either P-bit generation
is enabled or frame generation is enabled.
If C-bit generation is enabled, the bit C
bits (C
treated as payload data, and passed through. C-bit generation is programmable (on or off). Note: Overhead
insertion may still overwrite the C-bit time slots even if C-bit generation is disabled.
Once all of the DS3 overhead bits have been overwritten, the data stream is passed on to error insertion. If frame
generation is disabled, the incoming DS3 signal is passed on directly to error insertion. Frame generation is
programmable (on or off). Note: P-bit generation may still be performed even if frame generation is disabled.
XY
1
1
11
X1
1
, X
, P
, M
, C
2
2
2
X2
, and M
XY
, and C
) are overwritten with zeros. If C-bit generation is disabled, then all of the C-bit timeslots (C
1
3
1
and P
X3
and X
11
is the Application Identification Channel (AIC). C
Definition
Remote Defect Indication
(RDI)
Parity Bits
Multiframe Alignment Bits
Subframe Alignment Bits
Application Identification
Channel (AIC)
Stuff Control Bits for Tributary
#X
2
) are both overwritten with the calculated payload parity from the previous DS3 frame. The
2
) are both overwritten with the Remote Defect Indicator (RDI). The RDI source is
X1
, F
1
X2
, M
, F
11
1
Figure
2
X3
, M
, and M
is overwritten with an alternating one zero pattern, and all of the other C-
, and F
2
, and M
10-14.
X4
3
) are overwritten with the values zero, one, and zero (010)
) are overwritten with the values one, zero, zero, and one (1001)
3
Table 10-28
are the multiframe alignment bits. F
86
defines the framing bits for M23 DS3. X
X1
, C
X2
, and C
X3
are the stuff control bits for
1
XY
and P
are the subframe
2
are the parity
XY
) will be
1
and X
2