Pittsburgh telephone exchanges

The history of the telephone exchange names in Pittsburgh, as in most significant United States cities, can be divided into three periods:

1. The pre-dial period, when all telephone calls were completed by manual action by operators, and there were no constraints on exchange names other than that there was no likelihood of confusion when a customer gave the name to the operator,
2. The early dial period, in which the Pittsburgh telephone numbers were set up to accommodate dialing the first two letters of an exchange name followed by a four-digit number designating the individual line, though in fact not all exchanges provided for dialing by the phones in those exchanges, and
3. The late dial period, whose beginning in Pittsburgh was on August 13, 1949, in which, instead of the first two letters of an exchange name alone, one dialed the first two letters and an "office number" (This was the terminology used in an early New York City directory, though it was not common terminology in this period), again followed by four digits designating the individual line.

Currently, only data immediately prior to, and immediately subsequent to, the 1949 transition are available. As more data become processed, they will be added to this site, but links to the other places in the table below are not yet functional.