Review on 🔌 Cablemax RS-232 LED Link Tester - DB-9 Male to DB-9 Female Connector by Brandon Kraemer

It does what it says it does and does it well. The LEDs give you a very clear idea of what is going on in your serial cable. The only downside is that this device is designed for a pass-through connection (one side is male, one side is female), but both sides have a female mounting screw. holes. That means you can't connect it to almost anything directly, as almost all serial ports on computers and even devices have holes for female screws as well. If you unscrew the screw holes with a hex screwdriver there will be a metal shield with them and you will have an unshielded connection. Your choice is to either live with it or take two M->F cables with both ends threaded and place them in the middle. I ended up using some Krazy glue to stick the metal shield to the plastic case, but without screw holes it probably won't do anything anyway. Just a note - you may need to hack something or get extra cables with the right ends to attach this to anything.