German ad agency Jung von Matt has created a YouTube "museum." Their page, The Museum of Obsolete Objects, may purport to honor old, out-of-use technologies, but really it's a showcase for the incredible interactive design work of the ad agency, and for that alone it's worth checking out.
Slide the timeline around, pick an object, and watch a little video to see how each technology was used. The content of each video (not to mention the list of obsolete objects) is a little thin. Why did Morse code become obsolete in 2007? Wikipedia provides the answer, but not the museum. A strange, robotic voice narrates a demonstration. In the example video below about pocket calculators, the calculator performs some highly complex math, such as one plus one equals two and 56 divided by 14 is four. The material of the videos is just not at the level that the site's design and animation merit.
Before touch tone button phones people had to use rotary phones to dial a number (and before that they used a telephone operator).
Place your finger in the hole that shows the number you want to dial and rotate the dial clockwise until your finger reaches the finger stop and let go. Repeat this process for each digit. Sometimes a pencil is used to dial instead of fingers so as not to break long fingernails.
For a 1, you can quickly tap the hang-up posts, or repeat at the correct speed for higher numbers. The manual dexterity needed to accurately tap out anything above a three or four is rare. This was a common way to circumvent a lock placed on the dial's '1' to thwart outgoing calls.
One remnant from these days is that people still mostly say "dial a number" instead of punch in or type in a number. The word dial is obviously connected with the round rotary dial mechanism.
Even modern electronic phones have a switch to choose "pulse or tone" dialing for places where TouchTone dialing is not available, or still costs more (phone tariffs are based on "delivering a service" regardless of the cost or savings of the service. Despite charging more for TouchTone dialing, it actually saves the phone company money since it takes less time to collect the digits to complete the number).
TouchTone dialing uses DTMF (dual tone multi frequency): one frequency for the column, another for the row. People with perfect pitch can tell what is being dialed by hearing the tones.