If you are a Ham (amateur radio operator) in the U.S. you know of MFJ Enterprises. It is a company everyone loves to hate but has at least one item from them. Affectionately known Mississippi Fine Junk, they are based in the same state. Named after not Mississippi but its founder Marvin F. Jue. Basically while they do make some low end radios, they are known for all the odd bits they make. The little cheap things which connect all the expensive items together. Such as antenna tuners, cables, adapters, keyers etc.
This is an MFJ-557 Practice Oscillator. Lets you practice your code or drive your XYL or OM crazy. I do believe the MFJ-557 is the most produced practice oscillator ever. It is a bit of steel, a tone generator and a cheap plastic key. What more could you want?
Another MFJ item I have is the “JimHandy” Keyer. It is advertised as a 2 Meter CW Interface. But is a Modulated CW (MCM) Keyer. Basically allows one to send code over a FM transceiver or other voice mode transceiver.
SO MFJ makes life simpler. Instead of making the box to conect A to B, you buy it from them. Its not fine craftsmanship or high tech but its cheap and available.
Or you can make your own. One could buy a MFJ unit for about $60 or build it yourself. $10 for the electronic parts, a board, a battery, a battery holder, wire, brass posts, head phone jack, head phone or powered speakers etc. Well it was fun building it. A kit based Keyer :