Abstract: An adjustable height mounting pedestal (10) for public or coin telephones (18) comprises a tubular upright post (12) having a plurality of arrangements of mounting holes (80) corresponding to varying telephone mounting heights ranging from a drive-up curb side height to a standard handicap access height. A backboard mounting enclosure (16) is longitudinally aligned with and overlapping the upright post (12) such that the backboard (16) adjustably slides along the upright post (12) during installation of the mounting pedestal. A single installer can accurately determine the center height of a coin slot (19) of the telephone (18) before mounting the telephone within the backboard mounting enclosure (16) by use of a coin slot center height indicator (141). The upright post (12) allows mounting of a backboard (16) and telephone at a selectively variable height, and also allows the mounting of a second backboard (16') and telephone at the selected height.