Using DTR and RTS

[Samir]

Hi:

I have a couple of questions about figure 1 in app note 1.  Do I need to pass both DTR and RTS through RS232 transceiver?  If yes then do I need two chips if using MAX232 or equivalent?

Thanks.

Samir

[Andy Ayre]

Yes you do. But I believe there are versions of the MAX232 which provide four transceivers in each direction. Some may even elimintate all those eletrolytic caps that you need with the plain MAX232. Check out the Maxim web site.

I think you can also use a few resistors and a transistor to perform limited level shifting and inversion, but whether that will work with all PC COM ports is another matter.