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Hi am trying to find out the required AT command set for a microcontroller to connect through rs232 to a modem and call a number. i can do so with hyperterminal with ATDT then number. is this sufficient for the pic to send this.
With AT set do i need to ECHO (E1)? Set Baud rate? Set Asyncronous(&Mn)
Any HELP please
Get the manual for the modem you are using. It should probably be ok with _any_ modem manual, since all modems shares a common command set. It is only when you need to do more advanced things, change the factory defaults etc that the manual for your specific modem might be important.
Whatever you can do using the hyperterminal, you can do directly from the PIC. Your modem doesn't know - or care - what hardware and software you use to communicate with it.
Hi thanks for your reply.
When i send ATDT then number followed by return stroke(using pic), The modem doesn't respond. Therefore hyper-terminal must be setting or sending more data. To make a connection in hyperterminal i have to set baud rate to 9600 and hardware to none. So do i need more AT commands??
Please help
"Your modem doesn't know - or care - what hardware and software you use to communicate with it."
Absolutely!
See:
http://www.keil.com/forum/docs/thread9113.asp
http://www.keil.com/forum/docs/thread9265.asp
Keil don't make PIC tools, so why are you asking this on the Keil forum?!
See: http://www.keil.com/forum/
Of course you have to set correct baudrate, number of bits etc. Some modems may support automatic baudrate detection, but don't rely on it.
When working with modems, start with making sure that you can send a simpel "AT" command, and receive an OK back. If the modem has echo enabled, you will get both an AT and an OK string from the modem.
Rembember that most modems wants a two-character \r\n end-of-line.
"Rembember that most modems wants a two-character \r\n end-of-line."
Incorrect.
Modems expect a single command line termination character - this is specified by register S3, and is usually CR.
There is also the response formatting character, specified by S4, that the modem sends at the end of its responses - this is usually LF.
Thus, at the end of a command you send CR, the modem echoes the CR and appends LF.