usb problems

[Colin Law]

On 12 October 2014 14:18, Gene Heskett <gheskett at wdtv.com> wrote:
>> RS232 specifies a min of +-3 volts up to +-15 if I remember correctly,
>> so +-5 should be fine.
>
> And is rated to take surges to at least 25 volts, usually more from most
> chip vendors.
>
> But is it enough to power the internal circuitry?  Or do these converters
> have built in charge pumps running on the +4.5 or so they can get from the
> USB port?  Its plugged into a powered hub, and its blue power led is the
> usual brightness.

They get their power from the USB port.  A silly question I know, but
you have got tx going to rx in each direction I presume.

Colin