|A trunking system is controlled by a computer know as a Site Controller. It can also be controlled by a Master Control Center (MCC), which works parallel with the Site Controller. The MCC and the Site Controller are linked to repeater sites by microwave or dedicated telephone circuits. The basic trunking system contains one channel that serves as a control or "handshake" channel, known as a data channel. Most trunked systems currently operate in the 800 MHz band, but there is no technical reason to prevent trunking from being applied to other bands.