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Troubleshooting and Repair
025-9416
131
♦
Data block(s)
Each data block contains one page. A TNPP packet can contain more than
one data block if each page contains the same routing information (same
header). This field is limited in size only by the 1024 character maximum
per packet.
The Model 640 supports both full capcode paging and ID paging for
TNPP networking. Each type of data block has a slightly different format.
See
Table 25
and
Figure 67
for details on the data block fields.
♦
End Flag
ETX “
♥
.” This field is 1 character long and remains constant.
♦
CRC-16 BCC
(block check code)
The CRC-16 is a 2-character error-detection protocol. Usually the CRC
information consists of strange looking control characters.
Communication errors are very unlikely to go undetected when using
CRC-16.
Here is how a typical capcode page packet might look on a PC:
J
DE000801015C AGNA@C0040067298888005
♥
=K
CRC
Header
Page Block
Because the delimiters in the packet are control characters, some terminal emulators might show
the funny characters like:
^ADE000801015C^BAGNA@C0040067298888005^C=K
Header Elements
The packet header is 12 characters in length and includes four
pieces of information. The header
structure is shown in Figure 65.
Destination address
(4)
Source address
(4)
Inertia
(2)
Serial number
(2)
Figure 65. Header Structure
Table 24 describes each header element and the possible values. Note that the “Example” column
identifies the element in the example packet above.
Table 24. TNPP Packet Header Fields
Example
Valid Entries
Description
DE00
4 hex digits
0001 - FFFF
Destination address - the node the packet designated for
08
2 hex digits
00 - FF
Inertia - controls the maximum number of “hops” in a network
0101
4 hex digits
0001 - FFFF
Source address - the originating node
Summary of Contents for 640 DAPT XTRA
Page 2: ......
Page 6: ...Statements vi 025 9416...
Page 20: ...Introduction 8 025 9416...
Page 26: ...Specifications 14 025 9416...
Page 96: ...Installation 84 025 9416...
Page 126: ...Optional Equipment Installation 114 025 9416...
Page 134: ...Voice Prompts 122 025 9416...
Page 174: ...Parts Lists and Schematics 162 025 9416 Schematic...
Page 175: ...Parts Lists and Schematics 025 9416 163...
Page 176: ...Parts Lists and Schematics 164 025 9416...
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Page 182: ...Parts Lists and Schematics 170 025 9416 Silkscreen...
Page 185: ...Parts Lists and Schematics 025 9416 173 Schematic...
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Page 190: ...Parts Lists and Schematics 178 025 9416 Silkscreen...
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Page 196: ...Parts Lists and Schematics 184 025 9416 Silkscreen...
Page 198: ...Parts Lists and Schematics 186 025 9416 RAM Disk 702 9386B ROM Disk 702 9389B...
Page 199: ...Parts Lists and Schematics 025 9416 187 TNPP Interface 702 9362C 2...
Page 200: ...Parts Lists and Schematics 188 025 9416 Terminal Block Adapter 702 9470B...
Page 201: ...Parts Lists and Schematics 025 9416 189 CONFIGURATION DIAGRAMS Dual Trunk Telco DID 024 0076A...
Page 202: ...Parts Lists and Schematics 190 025 9416 Dual Trunk Telco End to End 024 0077A...
Page 203: ...Parts Lists and Schematics 025 9416 191 Dual Trunk Telco E M 024 0078A...
Page 204: ...Parts Lists and Schematics 192 025 9416 Dual Trunk Telco Ground Start 024 0079A...
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