New to Arduino, help with RS-232

I've been told by a large group of people at the Maker Faire that is in my town, that Arduino is the current best MCU to use! So I'm hoping that this forum lives up to the second part of their claim that the community around Arduino is second to none. I'm somewhat familiar with C, as well as a little more familiar with JAVA. What I'd like to start off with is controlling my Audio Video Receiver with my ATmega328. I have an Integra DTR-50.1 if any of you are familiar with the line, and it has an RS-232 port, and I happen to have the full RS-232 protocol. I'm looming for some tips and/or forum posts with information as to how I could send out serial strings (commands) with this chip. Thanks in advance for your help and I look forward to paying it forward once I learn a little bit more!

it has an RS-232 port

If it's geniune RS232 (ie +-12v) you'll have to condition the signals to talk to the Arduino. If this is the case the Arduino's 0-5v MAY drive the DTR-50 but the 12v will certainly fry the Arduino.

you'll have to condition the signals to talk to the Arduino

That's the purpose of RS-232 Driver and Receiver chips. Do a search for '[u]MAX232[/u]'. The original MAX232 chip required external capacitors but there are other variants that do not.

Don

So what I need to find out is what voltage the receiver will respond to as far as RS232 commands. If it ill respond to 5v commands could I do this without adding another chip onto my 328? As a side note, what should I be looking for as to how to make physical buttons work? I've never done anything with MCU's before and so would like something to be able to read over with good, concrete information.

The “hardware” section of…

http://www.arunet.co.uk/tkboyd/ele1sp.htm

… has info on the level shifting issues, and solutions. Look in particular at the stuff about the Wulfden PA4B

Well I now have confirmation from the manufacturer that the control is in fact 5v, rather than 12, so I think that means that I won’t need a shield to make this project happen! I all of these posts that I’ve been reading about serial (RS-232) communication have got my head in a spin, so I’m hoping you guys might be able to point me in the right direction. The codes I’m trying to send are in a form similar to “!1MVLUP\r”. What type of codes would I use to send these commands to the Tx line of my RS-232 controlled AVR? Thanks for all the great help you have provided up to this point!