Push button selection unit - particularly for telephone instruments, uses communal and individual contacts

摘要

This push button selection unit takes into account various forms of code selection. It has communal and coding contacts which are spring-loaded and are suitable for multiple frequency switching or the grounding of diodes. It has particular application for telephone units and each key can be supplied with a button or hollowed cylinder. These displace in longitudinal grooves for operating the contacts. The unit has one guidance rib for the peripheral buttons in the key-field and the internal buttons have two ribs diametrically opposed.