Token passing
Token passing is a communication protocol used in telecommunications. The system uses a signal called a token to limit when a device can transmit on the network. Only the device with the token can transmit. When that device is done, the token is sent to the next device. With large transmissions, the token may move to the next station before the transmission is finished. The device has to wait until it gets the token back before it can continue to send data. The most well known examples of token passing are token ring and ARCNET.