wireless modem

As far as I know wireless modems are usually provided by Internet service providers offering wireless Internet access. The ones that I have seen are inserted into a USB socket. The effectiveness or actual speed depends on factors like weather conditions, and interference from other electrical/electronic equipment. Maybe you meant a wireless router combined with a modem. This type still needs to be hard wired to the telephone line. Computers with wireless capability, either built in or added, need not be physically connected to it. I use one for my home network, and there is no noticeable difference in speed. But if someone using the same router uses a download accelerator, then the other computer(s) will experience slowness in Internet access.