Chapter 5: Communication Protocol
Comms Cable
You will also require a cable that sits between the RS422 port of the K2 converter and the Frame. It should be
wired as shown below. (Tip: Cut the end off a CAT5 Patch lead and attach a DB9 Plug)
Appendix B: On Screen Display Message Processing Rules.
Available on SmartNet-V only
Due to the limitations of both the On Screen Display and the amount of available non-volatile memory in the
SmartNet it is necessary for the Host system to perform some pre-processing of the message to be displayed.
The message string needs to be parsed character by character and the values translated according to the
table below.
Please see the following page for a working example of these rules in the form of a Visual BASIC function.
DB9 cable ended plug
Function
UTP Wire Colours (RJ45)
1
-
-
2
RX-(A)
Orange
3
TX+(B)
White & Brown
4
0V
Blue
5
-
-
6
0V
Green
7
RX+(B)
White & Orange
8
TX-(A)
Brown
9
-
-
Characters
Translation Rule
Comment
“0” Through “9”
Chr$(Asc(sChar) - 48)
Subtract 48 from ASCII value of character
“A” Through “Z”
Chr$(Asc(sChar) - 53)
Subtract 53 from ASCII value of character
“a” Through “z”
Chr$(Asc(sChar) - 55)
Subtract 55 from ASCII value of character
“.”
Chr$(&H27)
Substitute the character “.” for ASCII value 0x27
“ “ (space)
Chr$(&H0b)
Substitute the character “ “ for ASCII value 0x0b
“:”
Chr$(&H26)
Substitute the character “:” for ASCII value 0x26
“/”
Chr$(&H28)
Substitute the character “/” for ASCII value 0x28
“””(Apostrophe)
Chr$(&H29)
Substitute the character “”” for ASCII value 0x29
“-”
Chr$(&H0A)
Substitute the character “-” for ASCII value 0x0a
“?”
Chr$(&H70)
Substitute the character “?” for ASCII value 0x70
“*”
Chr$(&H5F)
Substitute the character “*” for ASCII value 0x5f
“=”
Chr$(&H78)
Substitute the character “=” for ASCII value 0x78
“>”
Chr$(&H7A)
Substitute the character “>” for ASCII value 0x78
“<”
Chr$(&H7B)
Substitute the character “<” for ASCII value 0x7b
“(“
Chr$(&H61)
Substitute the character “(“ for ASCII value 0x61
“)”
Chr$(&H62)
Substitute the character “)” for ASCII value 0x62
