AV Routers and Selector Switches

How many sources, how many screens: switch or matrix?

A selector switch connects several sources to one display, and only one source is active at a time. A bi-directional switch can also work in reverse, sending one source to either of two displays, again one at a time. A matrix switch is different: a 4x4 unit can feed any of four inputs to any of four outputs at once. Pick a matrix only when two screens need different content simultaneously. For one screen and a few devices, a plain selector is simpler.

Bandwidth, connector type and whether it needs power

Match the switch to the signal. HDMI 1.4 tops out at 10.2 Gbps, enough for 1080p and 4K at 30 Hz, while HDMI 2.0 at 18 Gbps carries 4K at 60 Hz with HDR. Analog VGA, RCA and 3.5 mm audio switches are usually passive, but matrix and Cat-cable units often need an adapter in the 5 V to 12 V range. CCTV multiplexers are built for one camera standard such as AHD, so match the standard of your cameras before buying.

Questions about AV Routers and Selector Switches

Can I run a two-in, one-out switch backwards to split a signal?

Only if the listing says bi-directional. Basic switches work one way. Even a bi-directional model sends the signal to one display at a time, so it cannot show the same picture on two screens together.

Why does my screen say no signal after switching?

The source and display must complete a new handshake, which can take a few seconds. Poor cables, an unsupported resolution or a switch that cannot handle your HDCP version also cause it. Try a lower resolution to test.

Do I need a matrix switch?

Only if several screens must show different sources at the same moment, such as a meeting room with a presenter laptop on one screen and a camera on another. For one screen, a selector is simpler and easier to operate.