The ARC interface allows a collection of instruments, up to a maximum of 32, to be connected to a single serial interface on a PC or other computer system. Each instrument may then be uniquely addressed so that commands for that instrument may be sent and ignored by all other instruments connected to the interface. Additionally, ARC instruments may be used on a simple RS232 interface in non-addressable mode without modification. Available as an option is the ARCTALK software package for IBM compatible PCs. At the simplest level, ARCTALK provides realtime direct control of instruments on the ARC bus from the PC’s keyboard. However, it can be used more effectively to create complete ‘programs’ within which several instruments can be set-up and/or measurements readback; responses can be captured in a ‘response’ file for later use, eg. by another application which could, for example, generate a graph of the data.