It could be COM1; it just depends on how the device manufacturer sets up the
registry and what the installation of the CF card does to it.

There's absolutely no reason to try all possible COM ports!  As Chris said,
read that branch of the registry and find which COM ports are active.  You
may be able to tell, based on the driver name associated with them, which is
the one for your card, also.  If you have at most two ports, then you could
try both of those, but it's a silly waste of time to try five ports, if
there are only two valid COM names in the registry.

Generally speaking, all serial ports are going to just have receive and
transmit lines at their outputs in default locations (pins 2 and 3, if I
remember right).  Whether you need a null modem cable or not depends on what
each device actually does. *We* can't tell you without physically reading
the manual for your card, for the device at the other end of the cable, etc.

Paul T.

No, I'm not sure of anything.  You have the device, not me.  Look in the
registry - the system can tell you what drivers it have available
(HKLM\Drivers\BuiltIn) and which are active (HKLM\Drivers\Active).  That's
like me asking you specific info about my hardware.

-Chris

Hi,

Should I also need the null modem adaptor for CF card? This morning I
checked the registry and tried with all the possible ports there COM3,
COM2, COM9, COM5, COM8, but I did not see any CF indication in the
registry in an specific port. In other words, I had no success.
<<

You would not use a null-modem adapter with the CF card, unless you are
connecting to another PC or PPC.  If connecting to some other equipment
(such as a laboratory instrument) you would just connect using the supplied
cable without an adapter.

Every Compact Flash serial adapter that I have used (several different
vendors) assigned Com4 to that port.

Dick