Each of the three input channels asynchronously measures the input signals from each point on the input module, determines the respective states of the input signals, and places the values into input tables A, B, and C respectively. Each input table is regularly interrogated over the I/O bus by the I/O communication processor located on the corresponding Main Processor. For example, Main Processor A interrogates Input Table A over I/O Bus A.There are two basic types of Digital Input Modules: TMR and Single.For specifications, see Digital Input Modules on page 98.