Any computer with an Ethernet port can be converted into a GPIB controller or device with the GPIB-LAN controller. In controller mode, the GPIB-LAN controller can remotely control GPIB-enabled instruments such as oscilloscopes, logic analysers and spectrum analysers. In device mode, the GPIB-LAN controller converts the computer into a GPIB peripheral for downloading data and screen plots from the instrument front panel. In both modes, the GPIB-LAN controller interprets high-level commands received from the host computer and performs the appropriate low-level GPIB protocol handshaking.