To be excruciatingly code complainant, everything in your breaker box needs to be the same brand as the box. Thus I have a GE Surge Pro that plugs into the main busses like one more double pole breaker. Maybe since the Intermatic goes outside the box, it is OK for any box.
GE only claims to limit pass through voltage to 600 volts, enough to fry your computer, but not enough to fry its surge protector. They guarantee everything in the house that has a secondary surge protector.
I am not to worried about my cable. It goes directly to the cable company's modem, and then to the router I paid $10 for after rebate. From the modem it is ethernet cable I think would vaporize before carrying enough current to hurt anything.