Luis Moreira wrote:
> >From memory I think this was done by using one of the other pins, like
> RTS, CTS, DTR as the supply by driving them permanently high, but I am
> not sure.
> Best regards
> 			Luis
>
>
> -----Original Message-----
> From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf
> Of Peter Feucht
> Sent: 16 November 2007 12:39
> To: 'Microcontroller discussion list - Public.'
> Subject: [PIC]: RS232 to 5V interface without supply voltage
>
> Dear Piccers,
>
> I remember, that a long time ago I saw an application note for a
> RS232-to-PIC(5V) interface which worked without any external power
> supply,
> but it took the needed voltages from some pins of the serial port. It
> had
> just a RS232 9 pole Dsub and 3 Pins (Rx,Tx,GND) on the PIC side.
>
> I just googled but wasn't successful.
>
> Does anybody remember such an application?
>
> Thanks for any help and best regards
>
> Peter
>
>
>   
I believe Dallas Semi (now Maxim) sells such a device.

--Bob A
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