A fascinating combination of office furniture types in 1906!
The Adjustable Table Company of Grand Rapids, Michigan manufactured a combination table for both telephones and index cards. It was designed as an accessory to be stood next to one’s desk to accommodate a telephone at the beginning of the telephone era and also served as storage for one’s card index.
Given the broad business-based use of the card index at the time and the newness of the telephone, this piece of furniture likely was not designed as an early proto-rolodex, though it certainly could have been (and very well may have likely been) used as such in practice.