The Call Director was a multi-line 1A2 phone made by Western Electric for the Bell System. Similar phones were made under license by Northern Telecom and Stromberg-Carlson. They used vertical strips of six buttons, with 25 wire pairs dedicated to each strip.
The first design had light bulbs next to the buttons. Later versions had bulbs within the buttons. Phones were made with up to 30 buttons (five columns of six buttons).
The mechanical linkages were very complex. Pressing a button in one column would cause another depressed button, even in another column, to pop up.
The phones were wedge-shaped, with a sloping front panel and a curved back. Wall-mounting versions, and touch-tone models, were also made.
Call Directors were used by several U.S. presidents.