rs232 convertor - help needed

Hello guys

I am new to this forum and I would kindly need your assistance. I have to build a RS232 to analog convertor, and my colleague left me in dark (story is long, and sad). Although I was a very passionate electronist some 15 years ago, time have erased my skills... and I have to deliver fast such a convertor.

The convertor should:
- take the digital data from the serial interface and
- convert the signal into an analog linear range of current from 4mA to 20 mA

Could you help me with a schematic? I can (still) make the PCB. If someone can help, I can even arrange to pay something, after I discuss with my boss. From the BOM (which is the single information I still have on this project), seems that the project is comprising of:
- 1 x PIC16F876/873
- 1 x MAX232A
- 1 x MAX543
- 1 x MAX400
- 1 x 3.584MHz Quartz
- 1 x UA7805 voltage regulator
- and some resistors, capacitors etc.

I mentioned the above main components because maybe you can find fast such a schematic (supposing my colleague made the project correctly). I would be totally at your disposal with the full BOM, or any other information.

Thanks in advance,
Bogdan

You might check out Nigel’s tutorials and WinPicProg http://www.winpicprog.co.uk
They will at least get you past the serial part and maybe all of it.

Don't have a schematic, will have a look if I can find or create one.
I am thinking... the MAX232 and the PIC will be used to convert serial to parallel and the MAX543 (think it's an A/D converter) to convert the PIC's
outputs to your analogue level.

hi,

You may also need a AD694, 4 to 20mA transmitter.