I don't know if this device or these switches are interesting, or if the buttons are compatible with anything else. But considering how cheap it is at the moment, I thought someone might like to see it:
1981 Vintage Computer Devices Miniterm 1203S Early PC Portable Terminal 1203On eBay – currently $14.99 + $57.28 U.S. shipping

Gaze upon those nice spherical double-shots. Oh, and the
phone cups on the back:

If you're scratching your head and thinking "What th'...?":
In the early days of portable computing, phones—especially in places like hotels—were often wired right into the wall rather than plugged in, and extra phone jacks for modem cords were still years away.
So to use a computer over a phone, you actually inserted its receiver into rubber cups containing a speaker and a mic. The data signals between your device, and the one you were connected to over the phone line, were then converted to and from acoustic
audio signals, like the two devices were having a real conversation. These receiver converters, called
acoustic couplers, were also available as standalone peripherals.
Hmm—
Computer Devices, Inc. ... Raise your hand if you think this was a company run entirely by engineers. :?)