The RS-232 Generic Problem Solver Kit is a

real no-brainer

1. Choose two connectors which fit the equipment to be connected.
2. Choose a RJ45 cable of the desired length.
3. Connect the cable(s) to the connectors.
4. Adjust software settings and test the connection. If it works, you made it.
5. If it doesn't work: replace one connector by connector of the opposite type and test again.