By: Don McClatchie

          Air Gap network security sometimes referred to as “Air Wall”, and “Air Gapping” is a physical isolation method used to separate computers that need high security from any and all networks and other computers. This means no wired network cables may be attached and no wireless network interface controller (WiFi) connections can be used.

You can use an Air Gap relay switch to allow access to the network at certain times of the day and isolate the computer at other times of the day so in this way you can restrict network access to a narrowly defined time of day during which you could be monitoring the data exchanges.

In a totally Air Gap isolated computer system, all input and output data must come from external physical storage media like removable hard drives or USB flash drives, in this way the data can be better controlled and scrutinized before it is allowed into the computer. The downside of this type of total isolation is the time it takes to check the data to be sure that it is clean and free from harmful software before allowing it into the computer.  With no wired or wireless connection to any network or other computers, the network can be considered a closed system and security can be assured with few exceptions.

One of the exceptions is the use of van Eck phreaking, with this technique it is possible to intercept the electronic signals from the monitor, keyboard, or other electronic emanations from the computer and read them if you are physically close in proximity to the computer. This type of signal sniffing is referred to as van Eck phreaking and uses the Electromagnetic Radiation that all computers leak out.

If you detect some type of abnormality or problem with your computer  and you suspect a network attack may be underway, you may want to quickly disconnect the network connection and an Air Gap relay switch could speed up the reaction time for the network disconnect with no need to pull off network wires instead just flip a switch for total isolation.


The IPX-24 IP video A/B switch is a 24 Volt operated 2×1 IP video network switch that can be used as an Air Gap relay for complete isolation of any network connection. The IP network signal is switched using isolated relay technology so that all forms of data can be passed or blocked under the control of DC voltage. This switch will pass the P.O.E. Power Over Ethernet supply on the selected channel only that can be used to turn off any equipment not selected.

Air Gap technology is not only used for IP networks but can be used for Audio, video, SDI signals, and many other types of communications. In the Broadcast TV industry, it is sometimes advantageous to cut off a signal feed or switch to another feed quickly, or just to isolate a source under relay control. Stereo Audio isolation and A/B switching both require that two balanced signals be relay switched to create the Air Gap isolation. A balance audio signal has both a positive (Tip) and a negative (Ring) connection for each of the two Left and Right channels, that is 4 wires switching between to sources.


When you have a need for audio switching or isolation cut-off you can use a device called SAR-2. The SAR-2 is a Stereo Audio Relay A/B switch that is completely isolated and has balanced audio relay (Air Gap) switching controlled by an external DC control voltage. It comes in either 12 VDC or 24 VDC versions and has a removable screw terminal connector.


For switching or isolating a video signal or an SDI signal you can use the VS-24 a coaxial A/B switch that is controlled by an external DC voltage. It has high isolation and can be used for signal cut-off or signal routing in an A/B type configuration. This is a true Air Gap type relay switch with BNC connectors for video or SDI signals. It is available with 12 VDC or 24 VDC control voltage operation.

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