| Information: | This tube chassis is from the 024 / 026 card punch and 056 verifier. It was used to switch wire contact relays and each valve was activated by contacts and switches around the machine.
Strictly speaking, the machines could have switched relays directly from these contacts. It was rumoured that valves were incorporated in order to attract Customer Engineers with both mechanical and electronic skills. Later 029 card punches used transistors instead. |