Telephone numbers ranging from 1-3 digits first appear in the 1892-1893 City Directory.

Telephone numbers ranging up to 4 digits first appear in the 1905 City Directory.

Telephone numbers ranging up to 5 digits first appear in the 1917 City Directory.

Telephone numbers with standard 5 digits first appear in the 1950 City Directory.

Telephone numbers with 7 digits appear in 1959.

Telephone numbers with numbers only appear in 1968.