Q: Apple Airport Express

Well the main function is to extend your wireless network. So if you aren't doing that, then I'm not sure why you bought it in the first place.

You can plug some printers into the USB on the Airport Express to wirelessly print to them.

If it's in range of your current wireless network, it can take that signal and broadcast it further. It won't weaken your original connection but the extended part of the wireless network's speed will depend on how close it is to the original wireless access point.

So if your network normally reaches 50 feet from the wireless router, and your express adds an extra 25 feet (purely hypothetical numbers here), if you put the Express at the 40 foot range of the original station, it will then broadcast your network to a total of 65 feet.

Just remember that the Express will broadcast the same speeds it is picking up. So if you put the Airport Extreme at the very end of your wireless network, it will most likely broadcast a weaker signal. When extending a network, the Airport Extreme just extends the wireless broadcast that it is receiving.

Best of luck!

AirPort base stations: Setting up and configuring an extended wireless network (802.11n) - Apple Support

Wi-Fi base stations: Extending the range of your wireless network by adding additional Wi-Fi base stations - Apple Suppo…