CCTV Camera Pros VM-Q401A CCTV BNC Color Quad Processor | Analog Security Camera Mux | Video Screen Splitter | 4 Channel Multiplexer

I have 4 cameras with sound. RCA connection into a S-link for connection to monitor that came with the system.Prior to this it was 2 small monitors, switch between cams only able to see 2 at a time.Now, all 4 seen at once.BNC to RCA adapter. RCA 90 degree adapter just to cut down on rear length. Video connected.BNC 90 degree adapter. BNC to monitor.RCA sound input x4.RCA sound out x1. RCA to 3.5 cable into moitor.Each cam needed power. 4-Way split into 1 psu.Now have all 4 cams in quad view.