Initially there were very few logical errors, which were solved in eighteen months and the machine started to operate on a limited basis late in 1951. By early 1952 it was averaging 15-20 hours of useful time per week for solving mathematical problems. This unit contained all operating buttons, indicating lamps, control swithces, and an oscilloscope for aid in maintenance. This unit decoded orders received from the control and memory. This consisted of two identical units, each containing 64 acoustic delay lines.
Any disagreement stop the machine and give an abnormal halt indication.
This unit emited the clock pulses at intervals of 1 microsecond, and timing pulses at intervals of 48 microseconds.