Current Loop to RS232 Converter

Hi,

I would like to build a current loop to RS232 converter but have been batteling to find a circuit. I am looking for anything from 25mA to 40mA as I would like to finish a project I am working on. Does anyone know where I can find a circuit and parts list for such a device or does anyone have one? Any assistance will be greatly appriciated

Thanks in advance

Shaun22 said:

Hi,

I would like to build a current loop to RS232 converter but have been batteling to find a circuit. I am looking for anything from 25mA to 40mA as I would like to finish a project I am working on. Does anyone know where I can find a circuit and parts list for such a device or does anyone have one? Any assistance will be greatly appriciated

Thanks in advance

Click to expand...

It used to be quite common, but I haven't seem a circuit for many, many years - I can't even remember now what the current used actually was (although 20mA sounds vaguely familiar!).

I did have a nice simple circuit at home somewhere, I'll see if I can find it, but I'm fairly doubtful that I can now.

From what I can remember, it's quite easy to do - I'm sure someone else will have more recent info.

Hi Nigel,

Thanks for the response, yes a 20mA circuit is an industry standard although I require a higher current rating, I dont think it will be too difficult to modify the circuit to suit the current. Thanks anyway.

You were not specific as to what type of current loop converter you needed, but here is one for TTY-RS232 current loop.
http://www.e-insite.net/ednmag/archives/1998/080398/16di.htm#circuit

There are a few others listed on this site depending on application.
http://www.discovercircuits.com

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