User's Manual

6. User Serial Port Commands
6.1. Overview
The asynchronous 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 user port, 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 user port. This is the default operating
condition of the RF modem. No special characters, hardware control lines, or
timing is required to operate the FireLine modem.
There is also a “Command Mode” used to program and configure the
FireLine. In the Command Mode, the FireLine modem accepts commands
via the serial port TxD pin. The commands can be used to change certain
internal parameters of the FireLine modem as well as to read-out the current
configuration and diagnostic statistics.
6.2. Command Mode
The FireLine modem may be put into a “Command Mode”, by entering a
sequence of three plus characters (+++). To keep the FireLine 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 FireLine modem first enters the Command Mode, it sends the
phrase “FireLine” 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)
6.3. Setting a Parameter
To set a parameter in the FireLine 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
FireLine modem to 1234, enter the following command:
ATDT 1234 <CR>.