And this one if for my Radio Shack RS232 DMM ....


Protocol
It looks like the DMM uses RTS and DTR to power the serial port. DTR
needs to be set to +12 volts and RTS must be set to -12 volts. The port
should be configured for 7 data bits, no parity, and two stop bits
(7,N,2) at 1200 baud. Take a reading by sending a "D" character to the
DMM and then read characters from the serial port until a carriage
return is found. The format of the returned data is a 13 character line
terminated by a carriage return. 
Byte)  12345678901234
Ex.1)  DC-1.9999 V  CR
Ex.2)     1.9999MohmCR


	
Good Luck,

	
Jim

				 

-----Original Message-----
From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
Of Richard Prosser
Sent: Thursday, January 18, 2007 5:00 PM
To: Microcontroller discussion list - Public.
Subject: Re: [EE] Extech multimeter RS-232?

I don't know about the Extech range but the Escort DMM I have uses
4800baud, 7 data bits, & I can't remember parity etc. So you may have to
try a number of variations even before you try the command set.

RP

On 19/01/07, Bob Barr <bbarr@california.com> wrote:
> I'm trying to use the RS-232 feature on an Extech multimeter.
>
> Specifically, I'm looking for the RS-232 setup (baud rate, data bits, 
> parity, etc), and command set for the RS-232 interface to an Extech 
> model 380289 multimeter. I've had no success searching for the 
> device's operating manual. (It's a discontinued model so the manual 
> isn't available at the Extech site.)
>
> I've also tried all of the usual combinations talking to it with 
> HyperTerminal but I still get no response from it.
>
> So far, I've gotten no reply to an email that I sent to their tech 
> support department.
>
> Can anyone give me a clue as to how to talk to this little beastie?
>
>
> Regards, Bob
>
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