[portable] - Cie 542

And the world changed.

While the official number has been superseded, "CIE 542" persists in legacy system manuals, technical exam questions, and older maintenance logs. cie 542

A CIE 542-compliant loop must reject common-mode noise up to 100 V RMS (50/60 Hz) and series-mode noise of 10 mV peak-to-peak without exceeding ±0.1% error. And the world changed