User's Manual

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 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 M7 modem.

There is also a “Command Mode” used to program and configure the M7. In

the Command Mode, the M7 modem accepts commands via the serial port

TxD pin. The commands can be used to change certain internal parameters

of the M7 modem as well as to read-out the current configuration and

diagnostic statistics.

4.2. Command Mode

The M7 modem may be put into a “Command Mode”, by entering a sequence

of three plus characters (+++). To keep the M7 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 enterin

he default sequence for enterinThe default sequence for enterin

The default sequence for entering into AT Command Mode:

g into AT Command Mode: g into AT Command Mode:

g 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 M7 modem first enters the Command Mode, it sends the phrase

“M7” 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 M7 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

M7 modem to 1234, enter the following command:

ATDT 1234 <CR>.