In article o.uk,
"Dave Liquorice" writes:
On Sat, 11 Jul 2009 15:27:05 +0100, Dave Plowman (News) wrote:

It's for the serial port on a PC. According to the blurb with the device
I'm connecting to it pins 1&9 have 5 volts DC on them to power things
like Bluetooth.

RS232 DB9 pin 1 is Carrier Detect and pin 9 Ring Indicator so this
port is non-standard. I assume this non-standard port is on the bit
of kit you want to connect to the PC and it just has the abilty to
power a Bluetooth device if required.

There are a number of serial port boards which can be jumpered to
provide 5V or 12V outputs for powering the attached device. I have
one in my collection upstairs somewhere. (At one time, I did quite
a bit of work on the Solaris serial port driver, which necessitated
getting a wide selection of different boards to test it against.)
The other way to do this is to force DTR and RTS to known states,
and then use them to power a low-power device, and I've done this
a few times. At least Dave's device seems to be behaving as a DCE
and the power is provided on what are normally DCE outputs, so it
should be benign if plugged into a DTE with a 1-to-1 cable.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]