This standard BS EN IEC 60122-4:2019 Quartz crystal units of assessed quality is classified in these ICS categories:
31.140 Piezoelectric devices
IEC 60122-4:2019 is applicable to crystal units with thermistors mainly used in the field of mobile communication that requires high frequency stability such as local reference signal generator for the mobile phone base station or GPS. This document provides users with technical guidelines of crystal units with thermistors as well as basic knowledge of common crystal units with thermistors