A Satellite Modem is used to transfer data from one site to another using a satellite as a relay.
There is a wide range of satellite modems available depending on their intended use. Some are designed for high speed trunking for backhaul type applications where the ultimate goal is to be as spectrally efficient as possible and others are designed to minimize the remote cost for a multi-site network.
Which satellite modem is right for you will depend on your application.
Below are some of the more common modems on the market: