John,
Dave Nadler's site explains this is detail, and Paul Remde (Cumulus
Soaring) has good advice also, including suggesting to visit Dave's
site:

"Connecting to PCs that Don't Have RS-232 Serial Connectors
Most flight computers and flight recorders connect to PCs using RS-232
communications. However, most new PCs do not have RS-232 serial
connectors. These are usually DB-9m (9-pin male) connectors. There
are several ways to work around that issue. My recommendation is to
use an RS-232 serial port PCMCIA Card. You can see an example he
Socket Serial I/O PC Card Another solution is to use a USB to serial
converter. However, many of these units to do work as well as one
would expect. David Nadler has compiled a very nice list of devices
that have been tested and work well. You can see his page he
http://www.nadler.com/sn10/SN10_USB_Serial_Notes.html"

Paul, hope it's okay to paste your info here as a plug.
~Bruce