Testing a vacuum tube (or valve in the UK) requires setting a number of parameters for that particular tube. As a result, tube testers can have very complex panels with many knobs and settings. Several tube testers, including the Soviet L1-3 and L3-3 models, used punch cards to automate the setup. The L1-3 was introduced in 1963 and the L3-3 in the 1980s .

To test a tube, a card is placed on the patch board on the machine's face. Configuration pins are pushed into the patch board through the holes in the punch card (see cryptomuseum.com).

See also Hickok Cardmatic 123R.