> Bob Blick <bblick <at> sonic.net> writes:
>
>> No, the E is at +5 volts. The resistor pulls down.
>
> Ok. I Imagined the scenario where the E is connected to RTS or CTS through
> a
> resistor. That way the circuit functions as 'collector repeater' and does
> not
> drain power from the PIC supply (which is usually very wimpy when powered
> by the
> serial signals).

But if you're powering the PIC from the handshake lines, anyway, how does
connecting the transistor buffer to them versus the PIC VCC any different?
There's no quiescent drain when you use a PNP transistor.

Personally I've never been much of a fan of scavenged power, since I have
owned several laptops each with at least quirk per port.

Cheerful regards,

Bob


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