DECODE PRM4 Benutzerhandbuch - Seite 12

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4 AT command set

The device's parameters can be altered by using the AT command set. The commands

are sent to the device by using the terminal program (HyperTerminal or similar) over

the serial RS232 port at the speed 9600bps with 8 data bits, no parity, 1 stop bit. The

modem device accepts the commands only in command mode. Changing the mode of

the device from data transfer to command can be achieved in two ways:

 While turning on the modem, press and hold the SET button on the front

panel, – the device will start-up in the command mode.

 If the device is already turned on and in the data transfer mode, the command

mode is entered by sending the array that consists of the character repeated

three times within the given time frame. Before and after the array, the pause

in sending must be made. The pause intervals before and after the sequence

must be of the same duration. The default character for this purpose is ASCII

plus sign. Therefore, to enter the command mode "+++" sequence ought to be

sent. The pause time interval is set in ms by using the ET command. The

default value is 1000 (or 1s). Bearing in mind the default setting, the command

mode is entered by sending the following sequence:

In both cases the modem will respond with OK when the command mode is entered.

If SET button is used for entering command mode, serial port parameters will be

fixed: speed 9600 b/s, format 8 data, no parity, 1 stop bit. If sequence "+++" is used

for the same task, modem will keep data formats used during data transfer mode.

Each AT command consists of the command itself and, optionally, additional

parameters. At the end of each AT command, the Carriage Return (CR) character

must be sent. On keyboards, it is usually the new line or Enter key. The modem will

also accept the Line Feed (LF) character as well as CR LF and LF CR combinations.

The parameters can be entered in both the decimal and hexadecimal numeric systems.

For example, to set a network address both ATNA10779 and ATNA0x2A1B can be

used.

By using the ATDC command, all set parameters and their values can be listed.

Below the manufacturer name and type of the device, the frequency range and

firmware release date are listed. The device output, as a result of ATDC command, is

given in the following frame:

Radio modem PRM4 868MHz /User's manual V1.6 / 24.05.2011

pause 1s "+++" pause 1s