H A Y E S A T C O M P A T I B L E C O M M A N D S E T
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© RF Innovations Pty Ltd, 1998
Page: 51
223889, Revision 2.2
7
The Hayes
TM
Compatible AT Command Set
he RFI-9256 supports many Hayes
compatible commands and command sequences, this enables
users and operators to fully control and operate the Radio Modem and in most cases emulate land line
or phone modems for their communication needs. Some commands are implemented for completeness
only and do not perform any function.
The Hayes
commands may be entered manually through a terminal or automated through dialer
programs and scripts. Most commands, with exception of the ‘%’ register (Table 7-5) and Connection
Commands (Table 7-3), may be concatenated into a single command string. Commands or command strings
must be terminated with a Carriage Return <CR> code produced by the Enter key. AT Commands may
be used if the terminal attached to the modem will not understand the menu system, for example a PLC
terminal. In addition to the modem configuration, AT Commands are used to dial and hang-up the remote
modem for Point to Multipoint Communication.
The AT Commands
The AT commands are a group of special commands recognised by your modem. These commands
derive their name from the letters AT, which are used to prefix commands. Before continuing:
Run your communications software and enter local mode (or terminal mode) at 19200-
baud, 8 bit data, No parity, One stop bit and no flow control or handshaking. If these values have
been changed for the modem then the communications software needs to be set the same as the
unit it is communicating to.
The Attention Code
An AT (sometimes known as the ATtention code) usually precedes all commands being sent to the
modem. It is used to gain the modem’s attention, informing it that you are about to send a command. For
example:
Type the command: ATI2 <CR>
Your modem’s firmware identity message will appear on your terminal screen. If you type I2 only, your
modem will not respond.
You may enter the attention code in all upper case, or all lower case letters, such as: AT or at
Multiple Commands
You may place multiple modem commands after an AT provided the total number of characters does
not exceed 255. For example, a valid command to display the modem’s internal temperature twice is:
T
