The silver pin is the hook up for the external antenna. Most phones have a little rubber plug on the back of them that fills the hole for the external antenna. I'm not familiar with how the V600 looks having never owned one, but I would guess on the back above where the battery is you will find a little round rubber plug. Remove that and then the pin should fit right into that hole. This gives improved reception as it allows your phone to use the car's antenna instead of its own.