VOIP and your alarm system

Thinking of switching your telephone service? Have you considered the impact that service changes will have on your alarm panel’s ability to communicate? 

VOIP / Digital Telephone Service

There is a trend lately of service providers offering packaged deals that include cable TV, internet, and digital telephone service. Unfortunately, they tend not to inform their potential customers that the phone service provided in these deals is digital telephone service / VOIP (voice over IP). There are advantages and disadvantages to this kind of phone service and you need to know what to expect before making a decision. 


1) Some SMDR or tone driven communications devices may not be compatible with VOIP lines. This includes most modems, including alarm panel dialers. The tones generated and transmitted by alarm panels to communicate with the central station are garbled due to the latent nature of VOIP, effectively blocking alarm panel modem communications completely. There are other methods of communication that can be utilized by alarm panels, but requires additional equipment to be installed at your expense.

2) Fax machines & credit card readers. We’ve had more success with these devices working through VOIP, but not 100%.

3) Power failures may also compromise VOIP lines. First, you should invest in a UPS with battery backup to maintain power for your service provider’s modem because if there is a power failure and that modem is not powered up, you will not have telephone service. Additionally, the various sub-stations that serve the internet are more susceptible to power failure than land lines.

4) Voice quality. Most VOIP services reduce the bandwidth used to simulate your voice, which will change how your voice sounds compared to on a land-line.


1) Every package is different, but the primary reason our customers decide to switch to digital telephone service is to reduce their monthly payment and / or be able to make long distance calls for free.

In an ideal world each home would have 2 telephone lines. 1 that is digital / VOIP service for long distance calls and 1 land line for power failures and SMDR (modem) communications. The monthly cost of such a setup is typically not a ‘real’ option for most families, however. 

Please contact Summit Diversified Systems if you want more information regarding telephone service changes or if you are concerned about an SDS alarm panel losing its communication path from a telephone service change. We will be happy to discuss the options available for maintaining panel communications should you consider choosing digital telephone service.

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