". Below, some common rules applying to the remote control message syntax are summarised.
Parameter names always are of lower case letters, four characters long.
Non-numeric parameter values always are written in upper case.
Numeric (floating point) values may be specified with an arbitrary precision, however the device will
reply only a fixed number of places. The receiver recognises a decimal point ('.'), numbers must not
contain any commas.
There must not be any whitespace in front or after the '=' in a message.
If the command/query is not of the form name=value or name=?, the receiver replies the message ?
SYNTAX.
If the message syntax is OK, but contains an unknown parameter name is used, the reply is ?
UNKNOWN
Numeric parameters are cut to the limits defined for this particular parameter.
Misspelled choice values cause the receiver to set the first value of the choice list.
Assigning a value to a read-only parameter will cause no fault, however the beacon receiver will
overwrite this parameter immediately or some seconds later with the actual value.
For computer based remote control from a monitoring & control application, the LBRX-1MT provides a
framed protocol with start/stop characters and checksum. With the framed protocol, the receiver expects
each message to be packed into a frame as described below.
char # example description
1
{
start character, always '{'
2
A
device address, always A
3
l
first character of the message body
.
e
message body ...
.
v
..
.
l
..
.
=
..
n-1
?
last character of the message body
n
}
end character, always '}'
n+1
.
checksum
Responses of the receiver are packed the same way. The checksum byte is calculated using an algorithm as
implemented by the following formula:
This protocol type is known as MOD95- or Miteq protocol . The receiver also packs it's reply in a protocol
frame as described above. incomplete frames, checksum errors or address mismatches let the receiver ignore
the message. The time between the characters of a message must be less than 5 seconds or the receiver will
treat the message as incomplete.
The receiver automatically detects if it gets accessed through the framed protocol and subsequently disables
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www.satnms.com
LBRX-1MT-UM-2002 Page 10/21
