On Thu, 18 Mar 1999, nhamoudi wrote:
> Hello,
> I need help about the serial port of the PalmPilot.
> I have a small device, which I can connect to the serial port of a PC.
> I want to connect this device to the serial port of the palm, but I don't
> know if it is electrically possible. Indeed, the device need some power to
> work (this power was supplied by the serial port of the PC).
> Can the serial port of the palm supply this little device with
> electricity, as the
> PC done.
I don't speak for palm, and don't blame me or them for anything that
happens, but I use the serial port for lots of things I am not supposed to
(MIDI, engine controller diagnostic ports, etc.), so I have some ideas :).
1. Using the modem sync cable, the port presented to the device looks very
close to what the PC sees, at least the pins that are implemented.
2. TXD and RXD do what you expect. For control signals, RTS and CTS are
active (and may not work the way you think), though DTR is available (but
nonstandard - see the developer info on www.palm.com/devzone that
describes the serial port pins). These signals are normally only active
when the serial port is open.
3. The serial port uses a level shifter and can only provide a few
milliamps. If your device uses less than 2 milliamps it should work. I
doubt a 10ma device would.
