Company Confidential
21
Raveon Technologies Corp.
BCD numeric encoding packs 4 bit BCD symbols 5 to a message code word into
bits 30-11. 0-9 are encoded as ASCII 0-9. Values beyond 9 in each nibble (i.e.
0xA through 0xF) are encoded as follows:
0xA Reserved (possibly used for address extension)
0xB Character U (urgency)
0xC " ", Space (blank)
0xD "-", Hyphen (or dash)
0xE ")", Left bracket
0xF "(", Right bracket
Over the air, BCD messages are normally space padded with trailing 0xC's to fill
the code word. The M8S output ASCII characters representing the numeric digits
as shown in this table:
Numeric
Digit
ASCII
ASCII Code
Numeric
Digit
ASCII
ASCII
Code
0x0
0
0x30
0x8
8
0x38
0x1
1
0x31
0x9
9
0x39
0x2
2
0x32
0xA
*
0x2A
0x3
3
0x33
0xB
U
0x55
0x4
4
0x34
0xC
space
0x20
0x5
5
0x35
0xD
-
0x2D
0x6
6
0x36
0xE
)
0x29
0x7
7
0x37
0xF
(
0x28
7.4. Alphanumeric Messages
When the pager receives an alphanumeric page, it outputs the charactors via its
RXD output pin on the I/o connector. The baud rate of the serial port is set with
the
ATBD
command.
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
