1. Tracked Changes. Signalling on low-voltage electrical installations in the frequency range 3 kHz to 148, 5 kHz. Low voltage decoupling filters - Generic specification Part 4-1, (25th April 2023) Authors: British Standards Institution, Record Type: Book Extent: 1 online resource (50 pages) View Content: Available online (eLD content is only available in our Reading Rooms) ↗