| 摘要 |
In a computer network of a base station and one or more remote units, data transmission from the base station to the or each remote unit is by way of a wireless (e.g. infrared) signal, and by way of a radio signal in the other direction. Infra-red receivers can be used in the remote units which are cheap and have low power consumption compared with radio receivers, and radio transmitters can be used in the remote units which have low power consumption compared with infra-red transmitters. This therefore facilitates the provision of cheap, battery-powered remote units. The wireless signal is used to send instructions to control selection by each remote unit of a transmission channel for its radio signals. |
