Yes running a cable to it is fine if you want to use it that way. If you use it that way its wireless is independent of your FIOS router (I assume the FIOS router also has wireless on it). But if you are talking about taking the wireless signal from the FIOS and rebroadcasting it with the wrt54g then you are really going to hamstring the wireless on your FIOS Router. You can try it and see if you like it. Wireless G has a max theoretical speed of 54Mb/s. That is about 25Mbit/s actual throughput with a perfect signal. If you have less than a perfect signal the speed will go down more. If you use the router like an extender then that cuts the bandwidth in half. So instead of 25MB/s max, it would be like 12.5Mbit/s max. This bandwidth is shared among all your wireless devices. Also if you happen to be on the same channel as a neighbor, then you must also share air time with them. If you used a wireless N device then your max rate to start with is much higher (max link rates of 150Mb/s to 450Mb/s depending on your WAP). Wireless AP links are usually the last choice if there is no other way to get signal to a location you need it at. Wiring an AP back to your router and extending the wireless that way is a much better solution if possible.