Apparatus for data bus expansion between two instrument chassis

An expanded address and data bus arrangement, comprising:

• a first interface circuit coupled to a first chassis having a plurality of slot positions for receiving circuit cards;
• a second interface circuit coupled to a second chassis having a plurality of slot positions for receiving circuit cards;
• and
• a cable coupled between said first and second interface circuits;
• said first interface circuit having detection circuitry for detecting its slot position and configuring its circuitry and direction of signal flow accordingly;
• said second interface circuit having detection circuitry for detecting its slot position and configuring its circuitry and direction of signal flow accordingly;
• said first interface circuit, said cable, and said second interface circuit being coupled in that order to form an assembly, said assembly being symmetric and reversible.