| 摘要 |
A method and an arrangement in a data network, comprising a centrally located master (M) and a number of slaves (S1-Sn) connected to the master via a bus (1-4), to control, from the master, the access of the slaves to the bus. When a slave has information to send, a first signal, which implies a request for permission to send (RTS1/RTS2.../RTSn), is transferred via the bus to the master. A scanning means (9, 10) in the master scans for first signals from the slaves only if no slave has a permission to send and, when a first signal is found, the scanning is stopped and a second signal, implying a permission to send (CTS1/CTS2.../CTSn), is transferred via a distribution means (11, 10) to the slave which has requested the permission to send. The second signal is transferred to the slave only as long as the first signal is transferred from the slave to the master. <IMAGE> |
