radio modem
Radio modems are used wherever data transmission is realized via radio links, with terminal devices that do not have radio facilities.
For example, notebooks can be connected directly to radio networks via radio modems or to cell phones via Bluetooth radio modems, which in turn can establish a radio connection to GSM networks, UMTS or Long Term Evolution( LTE). Furthermore, radio modems can be used to control sensors and actuators, connect RS-232 interfaces via WLANs or establish multi- channel radio connections in the ISM band.
Radio modems are modems that process and convert data signals and transmit them as radio signals. For mobile computing, radio modems are available as plug-in cards for notebooks, handhelds and cell phones that serve several GSM frequency bands and support both circuit-switched High Speed Circuit Switched Data( HSCSD) and packet-switched General Packet Radio Service( GPRS). To increase transmission rates, radio modems can use channel bundling. Furthermore, radio modems are available in the form of USB sticks as surf sticks.