How to Make DB9 F/F serial RS232 mini gender changer?
If all you need is a pure gender changer, I wouldn't bother making one because they're easy enough to buy:



Just search for DB9F Gender Changer or something similar.

You could make one yourself by getting two DB9F connectors and soldering nine short wires between them and using long threaded studs to link them together but it's a lot of work for nothing and it would probably cost you more in parts. But if you need to do anything more complex than simply changing gender, such as making a crossover adapter, you'll have to go down this path.

Check the data sheets for the USB converter and the meter to find out what connections you need to make.