Abstract: An information recording system having an electrical circuit for counting serially occurring pulses, the number of which is indicative of certain information, a memory storage unit adapted to be removably plugged into said circuit for connection thereto and having a memory containing a multiplicity of binary bit storage cells or character locations for storing binary data resulting from the counting of the pulses, a means connected in said electrical circuit and responsive to the connection of the memory storage unit to the electrical circuit for interrogating the logic bit state in each of the memory's character locations to determine if the stored logic states conform to a pre-selected code, and a display device, or other suitable means rendered effective by the interrogating means for signalling an operator whenever the logic state in any one of the character locations fails to conform to the pre-selected code.