This document has been declared "NONCURRENT". It is recommended, therefore, that this document not be specified for new designs. "NONCURRENT" refers to those documents which have previously been widely referenced and may continue to be required on some existing designs.

This document specifies minimum performance standards and test procedures for 100 foot increment automatic altitude reporting digitizer equipment. It is intended that this equipment be operated by a pressure altitude device whose accuracy requirements are the same as those applicable to the pilot's altimeter. The digitizer equipment is defined as the combination of components needed for conversion of an input equivalent to pressure altitude into parallel digital code set forth in the International (ICAO) Code for SSR Pressure Altitude Transmission. All automatic altitude reporting digitizer equipment manufactured under this standard shall comply with the requirements as specified up to its maximum range as indicated on the equipment nameplate. The digitized altitude output shall be in accordance with "U.S. National Standard for Common System Component Characteristics for the IFF Mark X (SIF)/Air Traffic Control Radar Beacon System SIF/ATCRBS and the International (ICAO) Standard Code for SSR Pressure Altitude Transmission.