Redirect Command Line to Com Port

Question

If I want to redirect a command line to a com port, I able to do so with:

ECHO Hello World > \\.\com4:

However, this is not working if the port is not open. If I use a program to open the port then close that program, the port is open, then this works.

My question is: How do I open a com port from the command line in Dos.

Answer 1

The mode command is used to initialise a com port, amongst other things.