Company Confidential
22
Raveon Technologies Corp.
Alphanumeric messages are comprised of a sequence of numbers and letters,
using 7-bit ASCII characters. Characters are encoded in 7 bit ASCII format and
assembled into the 20 bit message bits area of a message code word (bits 30-
11). Three seven bit ASCII characters use 21 bits so if the message is 3 or more
ASICC characters long, the first 20 bits of an ASCII message are in the first code
word, the next 20 bits of a alphanumeric message are transmitted in the next
code word, and so on. The 7-bit ASCII code is used for alpha-numeric
messages. There are 20 bits in each codeword for message data, however, in
this format each character is 7 bits. Characters are split between codewords and
the last codeword is filled with unprintable characters such as
end of
message
,
end of text,
or
null
. Null is the only character which can be
incomplete.
The maximum length for a standard alpha-numeric message is 40 characters.
7.5.
WMX and POCSAG Decoding
The WMX protocol may be enabled with the modem in the POCSAG mode. This
allows the user to easily read the ID that was decoded by the POCSAG receiver.
Details about WMX and code examples are on the Raveon website at
www.raveon.com/wmx
When a POCSAG message is received, and the WMX feature is enabled in the
unit (
WMX 1
command), then the M8T will output the decoded message wrapped
in the WMX frame format as shown below.
WMX Frame Format
WMX Frames are used to pass data into and out of a radio modem. The bytes in
the data field of the frame, field 6, contains the data that is transferred.
WMX Data Frame Format for Paging Reception
Field
Number
Bytes
Field Name
ASCII
Code
Function
