Table of Contents
Using Telephone Exchange Names
| Field | Telephone calls |
| Went Obsolete | 1960s |
| Made Obsolete By | all-number dialing |
| Knowledge Assumed | knowledge of how letters correspond with numbers on a telephone, and which words were associated with which exchanges |
| When useful | watching old movies, understanding very old signs |
Until the 1960s, telephone exchanges were identified by names, rather than numbers. The first two letters (in some cases three letters) would correspond with the number of the exchange. For example, a John Smith's telephone number would be published in the directory as UNiversity?-4605, not 86-4605. As cities switched from six- to seven-digit dialing, exchange names were phased out in favor of all-digit dialing, although some cities retained the two-letter prefix even with seven digits (e.g., UNiversity? 7-6807) well into the 1960s.
