1927 documentary on how to dial a telephone

Model 102

I'm always fascinated by the technology of thisgs tha we take so completely for granted - the development of the telephone is an excellent example.

The rotary dial is a device mounted on or in a telephone or switchboard that is designed to send electrical pulses, known as pulse dialing, corresponding to the number dialed. The early form of the rotary dial used lugs on a finger plate instead of holes. 

The modern version of the rotary dial with holes was first introduced in 1904 but did not enter service in the Bell System until 1919. The rotary dial was gradually supplanted by Dual-tone multi-frequency pushbutton dialing, introduced at the 1962 World's Fair, which uses a keypad instead of a dial...

Older candlestick model

The Model 102 telephone (B1 mount/set) was Western Electric's first widely distributed telephone set to feature the transmitter and receiver in a common handset. Prior models had been of the "candlestick" type, which featured a transmitter fixed to the base, and a receiver held to the ear. The 102 was manufactured between 1927 and 1929.

More on the history of these telephone models at youtube.

via Kottke.