How can I tell if fiber is available at my address?

I typed my address into RCN/Astound's site to check for service, and it offers me several options (300, 600, 1000, 1500 Mbps). But it doesn't specify anywhere whether these are coax or fiber. How can I tell which plans are the coax and which are the fiber ones? They also don't specify the upload speeds, which would also give me a clue which it is. Thanks