4.2.5 Types o f RCS Classes
e
O
VER
V
IEW
-
M
L
r
MULTI
M
EDIA
-T
ERMINAL M
MT-X,
M
MT-NT, E
OS
s
MULTI
M
EDIA
-T
ERMINAL M
MT-S
m
AVC-B
OX
, D
IGITAL
S
WITCHBOX
, A
NALOG
I
NPUT
B
OX
, H
ERMES
D2D,
H
ERMES
V2A, H
ERMES
DXD, H
ERMES
VXA
Table 4-4
4.3 How to calculate the checksum
The checksum is being evaluated from the recipient to make sure that the message received has not been
corrupted. The checksum is a kind of sum over all fields from
<TYPE>
to
<Body>
or
<TYPE>
to
<STATL>
respectively (Acknowledge).
The checksum is calculated by transforming each character of the message into its ASCII code. The
ASCII values are added, and this sum is converted into a hex number. The checksum uses the last two
digits of this hex number. If the hex number consists of non-numeric characters, these characters have
to be lower case characters.
Example:
Let's consider the addressing procedure. The command for the addressing procedure is
A.
m00Axx
xx is the checksum to be calculated. The
<TYPE>
of the message is
m
, the
<Body>
00A
message
m
0
0
A
ASCII code
109
48
48
65
Summing up
270
converting into a hex number
=10EH
<CHKL>
character has to be lower case!
e
<CHKH>
0
The correct addressing message :
m00A0e
Содержание Hermes DXD
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Страница 13: ...2 Summary This chapter gives an overview of the HERMES DXD ...
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