There's nothing in the modem that you can change that could block wireless access. The modem doesn't care what it's connected to-ethernet is ethernet, TCP/IP is TCP/IP.
However, you do need to remember to unplug power to the modem and power it back on every time you change the device connected to the ethernet port. It hangs on to the MAC address of the first device connected after each powercycle and won't talk to anything different until it's powercycled again.
This article shows the order to connect and power everything to get the network in sync the fastest.