Notes about telephony

If you’ve ever wondered why the numeric keys on a calculator resemble those on a phone (in the U.S. anyhow), but inexplicably backwards with the 7-8-9 at the top, or if you just like looking at old mechanical cash registers and other button-based devices, here’s an excellent read for you! Time to go dust off my own Burroughs Class 3…

Converting heat energy directly into sound using tiny electrical conductors is a 100-year-old idea for an alternative to the mechanical voice coil wire + moving diaphragm design of traditional speakers, but new research recently submitted to Applied Physics Letters demonstrates a new, actually feasible approach to making these speakers-on-a-chip. Still way too quiet and underpowered for use as a loudspeaker, but might have some novel applications in the near future as research progresses.

I like the name given to the 100 year old invention, though: the thermophone.