Abstract: With this method, a CSMA/CA protocol can be used for the transmission of data by means of infra-red light or radio (or other non-hard-wired transmission media). For this purpose a communicator that has a transmit requirement and has not yet received a bit identifies itself as an initiating communicator, and one that has no transmit requirement but has received a bit identifies itself as a receiving communicator. At the start of data transmission the initiating communicator sends a double length start bit (D) representing its identity and then waits a defined time (tc), during which the receiving communicator sends back an echo in the form of a single length start bit (B). The initiating communicator waits after each bit transmitted for the echo and compares this on receipt with the transmitted bit, its transmission being interrupted after a mismatch. After the data transmission, and provided there is no further transmit requirement, the identities of initiating and receiving communicators are removed.

Abstract: With this method the performance of full-duplex systems can be achieved with transmission of information using infra-red light or radio (or via other transmission media not involving hard wiring). For this purpose the two datastreams to be transmitted in opposite directions are brought to the same transmission rate. The time period (ta) between the beginnings of successive bits of a datastream are split during transmission into two equal halves (tb, tc), whereby the bits are transmitted during the first half (tb). A transmitting communicator switches to receive immediately after the transmission of a bit, whereas a receiving communicator switches to transmit after the receipt of a bit if it needs to send information, so that the transmitted bits of one datastream are sent during the second half (tc) of the opposing datastream.