usb to null modem diy

[BytePir8]

Hi all,
I'm making a usb 2 null modem cable,
for use in flashing my satellite box (DM800Hd se v2 )
I've got a prolific PL2303HX USB-to-Serial Bridge (usb to rs232 ttl auto)
and would like to know if any members could help
with wiring up old null modem cable (got an old damaged one to cut up)
out put pins on PL2303HX are,
3.3v
5v
TXD
RXD
GND

which pins go to what?
thanks guys,

Busy reading
it just ends up swamping my head
does it only need the tx/rx + grn/3.3v?
i see only the 5 pins on usb side, just need to find
the corresponding rs232 pins.


guys going to try this, advice?
will use the pins TX RX GRN pins usb side
and pins 2,3,5 on rs232 connector
Does this look right?
see attached pics, does it need power also?

RS232 pin out.jpgRS232 pinOut simple.jpg
prolific usb rs232.jpg

yep looks like i need power, 3.3v?

cheers
Guys
Byte

[DOUGALMCD]

Rx=2
Tx=3
Gnd=5
On the rs232