When the telephone was first introduced to households and offices, many of the procedures and courtesies that we take for granted weren't intuitive. In fact, a lot of newbie phone users experienced stage fright upon picking up the receiver. In order to help people adjust to this radical new technology, the Chesapeake and Potomac Telephone Company published handy little guides to proper telephone use.

Retronaut has a full series of these helpful tips and tricks. I'll admit to breaking one of their rules: concentrate while telephoning. The Chesapeake and Potomac Telephone Company foresaw all the multitasking that would occur while people spoke on the phone and didn't like it one bit.

How to Talk on the Telephone, 1917 [Retronaut]