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The Truth About VoIP Phone Lines and Medical Alert Systems

Your new VoIP phone line may sound OK, but is it powerful enough for a medical alert system to use in an emergency?

If you're like many Americans, your phone or cable company may have changed the way your home phone system works. Many customers are surprised to learn they no longer have Plain Old Telephone Service (POTS) that uses copper wire coming in to the home. Instead, they now have a digital phone line that uses the internet to transfer voice, using a new protocol called Voice Over Internet Protocol (VoIP). Since your number didn't change, and you are using the same phone line as before, you may not have even noticed a difference.

But there is a big difference, especially if you have a home alarm or a medical alert system.

Without going into all the technical specifications, here are the main differences between your old POTS-style phone service, and the new digital VoIP phone service:


  • Analog transmission, capable of transmitting both voice and data
  • Works during a power outage because electricity runs through the copper phone line
  • Being discontinued in many parts of the country, and POTS copper line networks are not being rebuilt when damaged in a natural disaster like a hurricane.
  • Expensive - one reason it's being phased out.
  • Fairly consistent quality of service among providers
  • Digital transmission, capable of both voice and data
  • Requires internet access
  • Inexpensive, and capable of lots of features at low/no cost like voice mail, three-way calling, call forwarding, fax, receive calls on a computer or tablet, etc
  • Often bundled with Cable TV and Internet services
  • Requires a battery backup if power is lost
  • If the internet is down, your VoIP line is down
  • Quality of service can vary during peak usage times, and depending on the usage in your neighborhood
  • Wide range of quality of service among providers
  • VoIP is provided through a Modem (box where your phone is connected). When service is switched from POTS to VoIP, you may lose connectivity in the other phone jacks installed throughout the home.

VoIP and Alarm Systems and Medical Alert Systems

Home alarm systems and Medical Alert Systems transmit DATA over the phone lines to the monitoring center. This is what establishes a connection and allows the monitoring center to know WHO and WHERE you are, and access your profile to know how to respond in an emergency.

VoIP phone lines generally can transmit VOICE at a quality level that is acceptable, but DATA is a different matter. Generally speaking, if you are using a high quality, national provider of VoIP service like AT&T, Comcast, Century Link, TimeWarner, Verizon and others you should be fine. However, due to low signal quality, VoIP phone service from providers like Magic Jack, OOMA and Vonage shouldn't be used with a medical alert system. In fact, these phone providers DO NOT recommend using their services with any medical alert systems. So, while you may be able to call across the country using one of these bargain-priced VoIP phone providers, you should NOT count on them to work with an alarm or medical alert system.

Examples of medical alert systems that work with both POTS and VoIP include the HOME Medical Alert System and the HOME & YARD Medical Alert System from Medical Care Alert.

How Do I Know If My VoIP Phone Line will Work With A Medical Alert System?

VoIP Test
If you have a VoIP phone line, please click this link to use the VoIP Testing Tool to determine if your VoIP phone line can support a medical alert system. Your results should show in the top part of the graph labeled "radio quality". If not, contact your provider and tell them you are connecting a medical alert device and need them to boost your signal strength. If they cannot do this, find another provider.

What About Cellular "Home Connect" Home Phones?

Verizon, T-Mobile, Sprint, AT&T among others may offer you a cellular "Home Connect" phone system that consists of one or more cordless handsets that connect wirelessly to a cellular "black box". Many people confuse this as a standard cordless phone system and think they have a land line phone. This is a cellular phone system, with a few handsets that only works within the range of the home. This is NOT compatible with ANY medical alert system. But that's OK - just ask for our HOME Medical Alert System with a cellular connection option.

Will My Medical Care Alert System work with my VoIP phone provider?

Your Medical Care Alert System requires a clear, strong, reliable telephone signal to ensure that both voice and data are clearly transmitted over the phone line to our monitoring center.

Medical Care Alert strongly recommends that a traditional phone line, known as Plain Old Telephone Service (POTS), be used for any type of alarm system, due to the much higher reliability of POTS.

However, we recognize that many customers have switched from POTS style phone service to newer digital formats – specifically Voice Over Internet Protocol, or VoIP. This is the type of phone service commonly bundled with Cable TV and Internet service from your local provider.

We are aware that when customers have switched from their POTS phone service, it is often no longer an option to get that service restored as phone companies are phasing that technology out. We are also aware that some customers have had their phone service changed from POTS to VoIP without their knowledge, or without understanding the full impact of the decision to switch.

The Medical Care Alert HOME and HOME & YARD systems are designed to be used with either traditional or VoIP based telephone service. However, it is important that you understand (as the subscriber and/or as the party paying for the service) that VoIP phone lines are more prone to service interruptions and fluctuations in signal quality.

Unlike a traditional POTS line, there are significant differences in the quality of service provided by different VoIP providers. You need to be aware that:

  • VoIP telephone circuits are not as reliable as standard telephone systems for various reasons, especially for data transmission.
  • Many Internet providers refuse to provide any service level guarantee, and clearly indicate in their contracts that service may be interrupted at any time.
  • VoIP circuits are dependent on AC electrical service to the residence, even if the VoIP system is equipped with a backup power supply. If you lose your power, and/or lose your internet connection, you will lose your phone service.
  • If your telephone service experiences service interruptions, you may not be able to use your Medical Alert System to contact our monitoring center.

For these reasons, your VoIP provider should be chosen carefully. Please evaluate the risks of not having your phone service available as part of making the decision whether or not to use VoIP telephone technology. Medical Care Alert will not assume any responsibility for alarms that are not received by the response center due to failures or interruptions in any telephone system used by the subscriber.

Here are important steps you can take if you use a VoIP phone service:

  • Test your system weekly
  • Inform your phone provider that you are connecting a medical alert device to the phone line
  • Only use a reliable VoIP provider. Services such as MagicJack are unacceptable for medical alert systems.
  • Plug your Medical Care Alert system directly into the modem. Use the splitter we provide to allow for both the Medical Care Alert system and your home phone service.
The following home phone service providers have been tested by our team over time. Be aware that company names and plans change often. Contact our Customer Service Team if you have questions at 877-913-3680.

  • ACN - unknown, too many variables
  • AT&T Uverse (VOIP Modem) - OK
  • AT&T POTS - OK
  • AT&T Home Phone connect - NO, Cellular
  • Basic Talk (Walmart phone box) - NO, Cellular
  • Brighthouse (Roadrunner) - OK
  • Broadstar - NO, Cellular
  • Centurylink (bought Quest) - OK
  • Comcast Xfinity (VOIP Modem) - OK
  • Cox Cable (VOIP Modem) - OK
  • East Texas Cable - NO, VoIP Incompatible
  • Excede Voice- (Internet phone) - NO
  • Fairpoint.com - NO
  • Fairview - OK
  • Fidelity Communications - OK
  • Frontier - OK
  • HTC (Horry Telephone Coop) - OK
  • Magic Jack and Magic Jack Plus - NO, Never, Do Not Use
  • Mediacom - OK
  • Metro Cast (VOIP) - OK
  • OOMA - NO
  • RCN (VOIP) - OK
  • Reedsburg Utility Commission Fiber Optic LightSpeed - OK
  • Service Electric (VOIP) - OK
  • Spectrum (VoIP) - OK
  • Sprint phone connect 2 - NO, Cellular
  • Straight Talk - NO, Cellular
  • T Mobile home service - NO, Cellular
  • Traditional landline (POTS) AT&T, Pacific Bell - OK
  • Verizon Fios -OK
  • Verizon Wireless home phone connect - NO, Cellular
  • Verizon Voice Link (wireless) - NO, Cellular
  • Vonage - NO, Never, Do Not Use
  • Windstream - OK, sometimes troublesome