Figure 6 - Multiple Monitor Connection - ADEMCO AMC21 Installation And Operating Instructions Manual

21-Inch Color Monitor
If you plan to loop the video out to another monitor, connect a cable to the
Video Out BNC and route it to the Video In of the second monitor. Up to
three monitors can be connected using the loop-through feature.
Figure 6 – Multiple monitor connection
Connect the power cord to the back of the monitor and plug it into the
power outlet.
6 AMC21