A mounting structure for mounting two pieces of equipment to a U shaped support arm structure of an equipment rack. The mounting structure includes an affixing structure supported by the support arm structure and a positioning structure affixed to the affixing structure at an adjustable position to define an adjustable size of the mounting structure. The first piece of equipment (e.g. a monitor) is mounted on the support arm structure, and is fixedly connected to one end of the mounting structure. The second piece of equipment (e.g. a KVM switch) is supported by the affixing structure. The positioning structure is fixedly connecting to the second piece of equipment near the other end of the mounting structure. Horizontal and vertical calibration devices help align the two pieces of equipment to enable two connectors of the two pieces of equipment to directly connect with each other without using a cable.