This question is about computers with front panels that use only
toggle switches for input of binary data, as opposed to keypads for
numerical input or other methods.

On these front panels, as well as state set by ON-OFF switches,
there's a need for momentary-contact switches for "commands" such as
examine, deposit, reset, start/run, and so forth.

In the 1950s either push buttons, such as on the [IBM 1620], or
momentary-contact toggle switches (that spring back to centre when
released), such as on the [PDP-1], were used, depending on the
manufacturer and model:

![IBM 6120 front panel][img1620]
![PDP-1 front panel][imgpdp1]

But by the 1970s, it seems that momentary-contact toggle switches were
by far preferred over push buttons, both for minicomputers such as
[various versions of the PDP-8] and the Data General [Nova] and
[Nova 3], and microcomputers such as the [Altair 8800], [IMSAI 8080],
and [Altair 680]:

![IMSAI 8080 front panel][img8080]

Was there any particular technical or ergonomic reason for this
seemingly wholesale move to toggle switches, or was it just chance or
fashon?


[IBM 1620]: https://en.wikipedia.org/wiki/File:IBM_1620.jpg
[img1620]: https://upload.wikimedia.org/wikipedia/commons/thumb/2/26/IBM_1620.jpg/320px-IBM_1620.jpg
[imgpdp1]: https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/PDP-1_control_board.jpg/320px-PDP-1_control_board.jpg
[PDP-1]: https://en.wikipedia.org/wiki/File:PDP-1_control_board.jpg
[PDP-8]: https://en.wikipedia.org/wiki/PDP-8#Versions_of_the_PDP-8
[Nova]: https://commons.wikimedia.org/wiki/File:Nova1200.agr.jpg
[Nova 3]: https://commons.wikimedia.org/wiki/File:Dg-nova3.jpg
[Altair 8800]: https://commons.wikimedia.org/wiki/File:Living_Computers_-_Altair_8800_(39802981903).jpg
[IMSAI 8080]: https://commons.wikimedia.org/wiki/File:Computer_Museum_of_America_(70).jpg
[Altair 680]: https://www.vintagecomputer.net/MITS/680/altair_680_front_panel_right.jpg
[img8080]: https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Computer_Museum_of_America_%2870%29.jpg/640px-Computer_Museum_of_America_%2870%29.jpg