Bus connection for plug-in electrical unit has variable resistance in plug-in unit, which also contains 4 bus switching arrangements for isolating control, signal, address, data lines

摘要

The device has a variable resistance (26) in the supply line to the plug-in unit (2) from the base unit (1) with a control input, high and low impedance states and an arrangement for isolating control, data and address lines from the base unit. The variable resistance is fitted in the plug-in unit, which contains four bus switching arrangements (281-284) for isolation of groups of control lines, signals lines, address lines and data lines.