Dallas-Fort Worth, TX
What happens to my business phones when the internet or power goes out in DFW?
When the internet or power goes out at a DFW office on a cloud phone system, the system itself keeps answering, because the call logic runs in the provider’s data center. Your desk phones go quiet. Whether callers still reach a person depends on rerouting to mobile apps or other numbers that you set up before the outage.
Book a DemoUpdated October 2026 · Cleod9 Voice, Arlington, TX
The cloud keeps answering
Your auto attendant, voicemail and routing rules run in the provider’s data center, not in your office.
Desk phones go quiet
VoIP desk phones need both power and internet, so they stop working when either one fails.
Reroute in advance
Inbound calls can go to mobile apps or other numbers, but only if that routing was built beforehand.
911 has limits
VoIP 911 may not work during a power or internet outage, so plan another way to reach help.
What keeps working, and what stops
A traditional phone system kept its brains in a closet. When the building lost power, the system lost power, and callers got endless ringing or a busy signal. A cloud phone system keeps the brains somewhere else. The auto attendant greeting, the voicemail boxes, the ring groups and the business-hours schedule all run in the provider’s data center, so they keep running while your office sits dark.
What stops is everything on your side of the internet connection. Desk phones need power, often delivered over the network cable by a PoE switch, and they need internet to reach the cloud. Lose either one and the desk phones stop ringing. The desktop app on an office computer stops too, and so does anyone on the mobile app who is still connected to the office Wi-Fi.
So the honest answer to “what happens” is this: your phone system is fine, and your callers are being sent to devices that cannot ring. Everything on the rest of this page is about closing that gap before it opens.
Build the rerouting before the storm
Each person’s extension is not tied to the desk phone. It also rings their desktop or browser app and their mobile app, so the phone in someone’s pocket can take a call that the dark desk phone cannot. That only works if the app is installed, signed in and allowed to ring, and if your routing sends calls somewhere that is still alive.
Write the plan down on one page and decide these points while the weather is calm. A plan that lives in one manager’s head does not help when that manager is stuck on an icy I-30 overpass.
- Which people answer the main number during an outage, and in what order should their mobile apps ring?
- Should the auto attendant play a short outage greeting, and who records it ahead of time?
- Where do calls go if nobody answers: a voicemail box someone checks, or a manager’s cell number?
- How is the switch made: automatically, by a rule built in advance, or by a person, and who is allowed to make it?
- Do the people on the list know that outbound calls from the mobile app show the business number, not their personal one?
- When did you last test it by unplugging the internet on purpose?
Battery backup: what goes on it
Many power interruptions are short: a flicker during a spring storm, or a few minutes while a utility crew switches a circuit. A battery backup turns those from dropped calls into nothing at all. The rule is simple: everything between the wall and the internet needs to stay powered.
The modem or the provider’s equipment that brings the internet into the building, because nothing else matters if it resets.
The router and firewall, which carry every call between your office and the provider’s data center.
The network switch, especially a PoE switch, since it powers every desk phone plugged into it.
Any Wi-Fi access points staff will rely on for the desktop or mobile app during an outage.
Ask whoever installs the batteries how long they will carry that specific load, and replace them on the schedule the manufacturer recommends. A backup that has quietly worn out over three Texas summers gives you a false sense of safety. For longer outages, the plan is not a bigger battery. It is the rerouting you built above.
A second internet connection
Battery backup covers a power problem. It does nothing when a construction crew in Lewisville cuts the line that serves your building, or when your internet provider has an area outage. For that, the answer is a second connection, ideally of a different kind or arriving by a different path, so one cut cable does not take out both.
A second connection only helps if your router can switch to it on its own, so ask whoever manages your network to set that up and test it. Also check how much upload the backup provides. Voice is light: Cleod9’s guide to internet speed for VoIP and video calls lists roughly 100 Kbps in each direction per call, and it recommends planning upload at no less than twice the minimum. A backup that keeps voice running while video meetings pause is often a sensible trade.
Not every small office needs two circuits. A three-person office whose staff can work from their mobile apps may decide that the rerouting plan is the backup. A busy front desk in Fort Worth that loses money every minute it cannot answer may decide otherwise. Cleod9 can quote a better business connection, whether dedicated internet access or business broadband, if your current one is the weak link.
Do this when the lights go out
Confirm what failed. If the internet is down but the power is on, your desk phones may show an error while the cloud keeps answering. If the power is out, assume desk phones are dark and switch to the mobile plan.
Have the people on the outage list open the mobile app and check that it rings. On a phone that is still holding onto office Wi-Fi with no internet behind it, turn Wi-Fi off so the app uses cellular data.
Make outbound calls from the mobile app, not personal dialers. Clients see the business number, and the call history stays with the business instead of scattering across personal phones.
Avoid these mistakes
Do not tell clients to call someone’s personal cell. Once that number is out there, it never comes back, and the call history leaves with the employee.
Do not start unplugging and rebooting the network gear one box at a time while the internet provider has a known area outage. You can turn a ten-minute outage into an hour of troubleshooting your own equipment.
Do not assume a desk phone can call 911 just because its screen is lit. If the internet behind it is down, it cannot reach anyone. Point people to a cell phone instead.
911 during an outage
Every VoIP provider is required by the FCC to tell customers how 911 works on its service, and part of that notice is a warning that 911 can fail when the power or internet does. Take that warning literally. A desk phone with no power or no internet cannot place a 911 call, so every office should keep at least one charged cell phone where staff know to use its regular dialer in an emergency.
Outages also scatter people. When an ice storm closes the office, staff end up working from home on the mobile or desktop app. Federal rules call for 911 calls to carry a dispatchable location, meaning the street address plus the floor or suite, and an app used at home or on the road counts as a non-fixed device. For a softphone or mobile app used away from the office, the 911 call should carry a dispatchable location where technically feasible, which is why the location on file has to stay current. Cleod9 supports Enhanced 911 with location information, but nobody outside your office knows when someone starts working from a spare bedroom in Denton, so update the records when people move. Our page on how 911 works on a VoIP system for a Texas office covers the rules in full. This page is general information, not legal advice.
A storm-season checklist for North Texas offices
Weather in Dallas-Fort Worth runs on a calendar, and so should your outage plan. Tie each check to the season that tests it, the same way you would schedule a roof inspection before hail season.
For a practice-specific version, see how we approach VoIP reliability for Grand Prairie healthcare offices, where a missed call can mean a missed patient.
- Before spring storm season: run a test outage by unplugging the internet, confirm calls reach the mobile apps, and re-record the outage greeting if anything has changed.
- Before summer heat: check that battery backups still hold a charge, since heat wears batteries down and summer heat strains the power grid.
- Before winter: confirm who works from home if roads ice over, and make sure their 911 location records show their home addresses.
- After any staffing change: update the outage call list and its order, and have each new person on it answer a test call on the mobile app.
- After any real outage: write down what worked, what did not, and how long it took to switch, then fix the slowest step.
Common questions
Do VoIP phones work when the power goes out?
Desk phones do not, unless the modem, router and network switch are on battery backup and the internet service itself stays up. The cloud side of the system keeps running, so the auto attendant still answers and calls can still be routed to mobile apps or other numbers, if that routing was set up beforehand. Staff with the mobile app on cellular data can keep taking and making calls with the business number.
Will callers hear a busy signal if our internet is down?
On a cloud phone system, the provider’s data center is still answering, so what callers hear depends on your routing. If calls are set to ring desk phones that are offline, callers may end up in voicemail or ring without an answer. If you have built rerouting to mobile apps or another number, callers reach a person and may never know your office was down. Test it before you need it.
Is a backup internet connection worth it for a small office?
It depends on how much a dark hour costs you and how well your staff can work from mobile apps. A small office whose people can answer from their phones may treat the rerouting plan as its backup. An office with a busy front desk, or one where staff must be on office computers to do their work, usually benefits from a second connection that the router switches to on its own.
How long will a battery backup keep our phones running?
That depends on the battery’s size, its age and how much equipment is plugged into it, so ask whoever installs it to estimate the runtime for your specific modem, router and switch. Batteries are best for riding out short interruptions without dropping calls. For a long outage, plan to move calls to the mobile apps instead of trying to buy a battery big enough to outlast an ice storm.
Can staff make outbound calls during an outage without using their personal numbers?
Yes. When staff call or text from the mobile app, the client sees the company’s number rather than a personal cell, and the record of the call is kept by the business. That is why the mobile app is the backbone of most outage plans: the person working from home during a power outage looks the same to a client as the person at the front desk on a normal day.
Can Cleod9 help plan our outage routing?
Yes. Cleod9 supports its own customers locally, so the person you work with on outage routing is in your time zone and can come on site if your network gear needs attention. Because the call logic lives in the cloud, inbound calls can be rerouted to mobile apps or other numbers when your office is down, but only if that routing is set up in advance. Bring a list of who should answer and in what order, and test the result with a planned outage.
Talking to Cleod9
An outage plan comes down to three things: power for the gear between the wall and the internet, a path for calls to reach people outside the building, and the habit of testing both. Cleod9 Voice runs on a cloud platform built on Wildix, maintained and updated remotely, and if your plan needs hands-on work in your building, someone from Cleod9 can come on site. For the bigger picture on where call problems start, read our page on how reliable VoIP is for a Dallas-Fort Worth business.
Before the next storm season, write down who should answer the main number when the office goes dark, and in what order. Bring that list to a demo and ask how those calls would reach each person’s mobile app.