What do you use to make your own studio and gear diagrams

[MarkTarlton]

I am wanting to make some handy diagram flowcharts for all the gear in my studio... I would like a picture with text on each individual piece of gear so I have all of my connections from the mixing board, hardware inerface, outboard pres and fx, patchbay, etc...see pic below for example.

What do you use for OSX? Free options are always good

Thanks!
 

[orthodox]

Free and simple: http://dia-installer.de/download/macosx.html

[MarkTarlton]

thanks orthodox!

just downloaded it