Provided you have the necessary video editing software you can use the i-link to transfer your video onto your computer.
'i-link' is the Sony trademark for their equivalent (identical as far as compatibility is concerned) to Firewire. I assume that Panasonic are using the Sony version as that is the more common used with video cameras.
As long as you have a cable the correct end terminations it should be a matter of 'plug and play'
A RS232C connection as far as I remember is one of the old either 9-pin or 25-pin type sockets used as serial or parallel port connections. This would probably be much too slow to achieve good downloads of digital footage.