What was used before pre-paid calling cards?
Telephone tokens! This article by Christopher Batio appeared in the January 10, 1995 Numismatic Review. Good reading:
Telephone Tokens: The Forerunner of the Telephone Card
"Before there were telephone cards to collect and use, telephone tokens were a widespread medium of exchange for people wanting to talk with someone across the ocean or across the street."
"These brass nickel-sized tokens were once widely used in Europe, Japan, and South America, and are still used today in places such as Turkey, Hungary, and Israel."
Israeli phone tokens, showing a telephone dial on the front