We take it for granted that when we pick up our phone, it will work. Somehow, it manages to get its power. I mean, you’ve probably never had to put batteries into your desk or wall phone before (with a few small exceptions). How then, is your phone powered? In the days of old copper telephone lines, phones would receive their power directly through the line itself. At the local telephone office, 48 volts DC would be sent down the lines. Then when the phone rang, about 90 volts AC would be superimposed over the DC. Once answered, the voltage drop significantly below the original 48 volts. That’s the old technology, but how does it differ from that of VoIP? Read on to find out.

The most commonly argued advantage to the old copper system was that, during some power outages, your phones could still work. This was because the central telephone offices have large arrays of batteries and backup generators. So, even though you would not be relying on your business’ or home’s power, you had to still count on the telephone lines being left in tact. But here’s what many often don’t realize, until they have it happen to them (like I have; several times!!) There’s a good chance that if power lines are damaged, phone lines will be, too; therefore, the phone systems New York businesses rely on, will not function. Just look at what happened during Hurricane Sandy. After that, some of the telephone lines (and especially in NYC) were so badly damaged, the phone companies began replacing them with fiber optic cables. Fiber optic lines do not carry power, but they can still carry non-VoIP telephone service. Just, in that case, you would still have to supply your own power to your phones.

VoIP phones will not operate when the power is down, unless you have an uninterruptible power supply. However, VoIP phones can be physically moved to a location that does have power. The telephone number will also stay the same, since that’s registered to the phone itself. You can’t do that with an older copper phone! This actually gives VoIP a major advantage over traditional copper service. The whole power debate has mostly affected consumers with residential service. Larger businesses, with PBX equipment, would still lose phone service if the power went out; even if their equipment was connected to copper telephone lines.

VoIP phones can actually be powered, in a very similar way to the older copper landline phones. With older landline phones, the cable that went into it, had anywhere from 2 to 8 wires. With VoIP phones, the cables have 8 wires. They’re standard ethernet cables. Here’s the thing, normal network speeds (100 mbps) only require 4 of those wires. A newer technology, known as “Power over Ethernet” (POE) takes advantage of the remaining 4 wires by sending power over them, to power up your VoIP phone. On gigabit networks (1000mbps), all 8 wires are being used for data. In this case, POE will still work, but the voltage is superimposed over the data lines.

If you’re not using Power over Ethernet for your VoIP phone, then your phone will need to be powered with one of those bulky power block adapters. Some very small businesses will operate, using these, but larger businesses tend to always go with POE.

POE has several advantages for powering VoIP phones. First, the power is supplied through a central hub/ethernet switch. This requires only one power outlet. Second, the alternative to POE is using a separate power adapter. These power adapters are bulky and have a tendency to burn out over time. Third, with POE, you can have the ethernet switch hooked up to a UPS (Uninterruptible Power Supply) and still power your phones during a blackout (but only for a short while; this also depends on whether your internet is still functional). Finally, since POE only requires an ethernet cable, this allows you to place VoIP phones where there are no nearby power outlets.

POE actually isn’t that far different than the kind of power that used to be sent over older copper phone lines. Like those lines, POE also sends 48 volts DC over the lines. Sometimes 24 volts DC is sent, but the VoIP phone will communicate its power needs to the ethernet switch and then the switch will send the correct voltage to the phone. This is why it’s safe to hook a normal computer up through a POE ethernet switch. The switch will only send power if it can definitively identify the device at the other end as requiring power.

Some quick tips about dealing with power outages. I had an article, a while back which covered this topic, but I’ll mention a few options here, anyway. If you lose power for your VoIP phone, most phone companies can redirect your calls to a cell phone. You can also use a smartphone app to access your VoIP service and still make and receive calls. But, oh no! How can you charge your cell phone if there’s no power? No problem! If you go onto amazon.com and type in “usb battery pack”, you’ll get tons of results for rechargeable batteries that you can plug your cell phone’s charging cable into. Some of these packs can recharge your cell phone 10+ times before they require being recharged again. That’s plenty to get through most power outages. The key here is to find one that has a larger amount of mAh (milliamps). The larger that number, the more power the battery is able to store. I would recommend going for the largest capacity that your budget permits. If you’re a business, then getting several might even be a good idea.

So there you have it. We’ve covered how older copper phone lines were powered, how VoIP phones are powered and how you can keep your cell phone powered if you need it during a blackout! I hope you’ve found this article to be useful. Thanks for reading!