Company Confidential
12
Raveon Technologies Corp.
4. User Serial Port Commands
4.1. Overview
The serial portion the RF modem is used to send and receive data over the
air, as well as to configure the RF modem. In normal operation, the user
sends data into the TXD pin of the IO connector, and this data is transmitted
over the air. Received data from another RF modem is output to the user via
the RXD pin of the IO connector. This is the default operating condition of the
RF modem. No special characters, hardware control lines, or timing is
required to operate the
M8
modem.
There is also a “Command Mode” used to program and configure the
M8
. In
the Command Mode, the
M8
modem accepts commands via the serial port
TxD pin. The commands can be used to change certain internal parameters
of the
M8
modem as well as to read-out the current configuration and
diagnostic statistics.
4.2. Command Mode
The
M8
modem may be put into a “Command Mode”, by entering a sequence
of three plus characters (+++). To keep the
M8S
modem from unintentionally
entering the Command Mode because of the +++ pattern occurring in a
stream of data entering the modem, there must be a pause in the data stream
before the +++ as well as a pause after the +++ is sent. If either pause is
missing, the modem will not enter the command mode.
Using serial communications software such as
HypterTerminal
, send the 3-
character command sequence “+++” while observing times of silence before
[BT (Silence Before Sequence) Command] and after [AT (Silence After
Sequence) Command] the command characters. The default BT and AT
times are 500mS.
The default sequence for entering into AT Command Mode:
1. No characters sent for ½ a second.
2. Input three (3) plus characters (“+++”) within ½ of a second.
3. No characters sent for ½ a second.
When the
M8
modem first enters the Command Mode, it sends the phrase
“
M8
” out it serial port, and then an “OK” sequence. The “OK” sequence is a
sequence of 4 characters:
An “
O
”, “
K
”, <
CR
>, and <
LF
> characters
(<CR> = ASCII 0D, <LF> = ASCII 0A)
4.3. Setting a Parameter
To set a parameter in the
M8
modem, enter the Command Mode as
described above. Then enter the proper AT command, a space, the
parameter, and then a carriage return. For Example, to set the address of the
M8
modem to 1234, enter the following command:
ATDT 1234
<CR>.
