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AC vs DC Switch: Which One to Choose?

September 28, 2021

To apply a switch in the network, the first step is to get the network switch powered up. There are two power types: AC(alternating current) power and DC(direct current) power for a Ethernet switch, both of which are used for increasing network uptime. Then AC vs DC switch, what are the differences and how to choose each in different applications? This article will give a detailed introduction.

AC Switch vs DC Switch: What Are They?

AC switch is usually equipped with a fixed AC power supply connector. To power it up, all you need to do is to connect the AC switch to the power socket with proper cables such as IEC/NEMA/Z-lock power cords. PoE/PoE+ switches are typical AC switches, take FS 8-Port Gigabit Ethernet PoE+ switch as an example, which is equipped with a single power supply (as shown below).

Figure1: FS S3150-8T2FP PoE+ Switch

DC switch can be configured with an internal or external DC power supply. And the external DC power supply is more popular nowadays, which is also known as redundant power supply. DC switch often has more than one redundant power supply, for it can protect other power supply when it fails with shorted outputs as well as power up the switch. Take FS 48-Port Ethernet switch as an example, equipped with 2 (1+1 redundancy) hot-swappable power supplies, it can still operate while one of the power supplies breaks.

Figure2: FS S5850-48T4Q Ethernet Switch

AC vs DC Switch: What Are the Differences?

What a switch doing in a circuit is to make or break the electrical connection, the speed of which really matters. In AC power, the arc of the AC switch can extinguish itself quickly. It is a desirable condition. While in DC power, it takes much longer for the voltage arc in the switch to be extinguished and may bring about pitting of switch contacts. However, DC power can provide smooth flow and even voltage, therefore most electronics use it such as to store power in batteries.

AC vs DC Switch, How to Choose?

So AC vs DC switch, how to choose? It depends on the types of power supplies you need in your network structure. Actually, there are also some switches applied with both AC and DC power supplies. However, if you use DC power supply to power up your switch initially, the switch will detect it and operate with DC power. In this case, AC power supply installed in the switch will be disabled. Remember not to mix AC and DC power supplies in a switch.

Then if we choose the wrong type of switches, what can we do? To use AC switch in DC location, a power inverter (changes DC to AC) should be added. DC switch can also convert AC power to DC power by using a rectifier. That is to say, when you choose a wrong DC/AC power switch, you have to buy another network device(power inverter or rectifier) as a remedy. While a second device is always needed, FS provides a switch that can operate in both AC and DC power supplies.

This FS 24-port layer 3 switch can be applied in dual AC/DC hot-swappable power supplies for 1+1 redundancy and load sharing. Also the AC/DC switch supports MLAG (Multi-Chassis Link Aggregation) for uninterrupted services with high reliability. Therefore it is ideal for large-scale campus network aggregations, small and medium-sized network cores.

Figure3: FS S5850-24S2Q Ethernet Switch

Conclusion

Both AC switch and DC switch are commonly used nowadays. AC vs DC Switch: which one to choose? It depends on the power supplies as well as your own case and needs. To avoid network disability and save time and effort on remedial measures, the dual AC/DC power supplies switch might be a nice solution for your network.

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