OSCYLOSCOPES SPECTROANALYZERS AND OTHER DEVICES AND APPARATUS FOR MEASUREMENT OR CONTROL OF ELECTRICAL QUANTITIES EXCEPT MEASURING 28 MEASUREMENTS 28 APPARATUS AND DEVICES FOR DETECTION OR MEASURING ALPHA BETA GAMMA X-RAY SPACE AND OTHER IONIZING RADIATION: - OTHER INSTRUMENTS AND APPARATUS SPECIALLY DESIGNED FOR TELECOMMUNICATIONS (EG METER CROSSTALK GAIN KOEFITSIYENTIVVYKRYVLENNYA PSOFOMETRY)