State system for ensuring the uniformity of measurements. Optics and optical instruments. Field procedures for testing geodetic and surveying instruments. Part 1. Theory
Signalling on low-voltage electrical installations in the frequency range 3 kHz to 148,5 kHz. Part 2-2. Immunity requirements for mains communications equipment and systems operating in the range of frequencies 95 kHz to 148,5 kHz and intended for use in industrial environments