As a SME on Telecom and owner of a wholesale VOIP carrier – I'd like to add my comments to the VoIP discussion on your forum.
1.       VOIP is replacing how analog (TDM) dial tone gets delivered. The conversion of TDM on the nation’s carrier’s backbone to VOIP happened 5+ years ago and we are now seeing the last mile convert. Even cellphone calls transverse the carrier networks backbone in VOIP.
2.       VOIP supports voice and fax (which is data). When ordering VOIP lines needed to support data (fax or dialers) request: 1. G711 format always (never compressed to G729) and 2. Add feature T.38. Any VOIP carrier who doesn’t know what this means isn’t someone you should be using.
    Bottom line is any VoIP line that will auto compress if internet isn’t good enough to support G711 shouldn’t be used.
Dean Garfinkel
Quality Voice & Data, Inc., President
516 656-5115
    The Standard Form Agreements and the Disclaimer Notice still warn subscribers in regards to using VoIP for alarms and recommend against it, going so far as to state that subscribers use VoIP at their own risk.  Every time I ask an alarm expert if it's time to change those provisions I'm told not yet.  Clearly some systems communicate over VoIP without incident.  
    Rob from Koorsen Fire and Security is absolutely correct. Do not mistake VoIP business communications with a path for alarm signals.
    Voice over Internet Protocol or VoIP is primarily designed for VOICE traffic. Any slight interruption of the IP channel, degradation in the service providers lines or even a power failure WILL interrupt the alarm communications or prevent it altogether. Who hasn’t had this conversation with an alarm customer: “My alarm went off last night and no one even called. What am I paying you people for?” I know my first question back to the client is “Who is your phone company?” The answer almost without fail: “Well we switched to (Comcast or Verizon FIOS) last month.”  A quick visit to the residence shows the alarm either cut off completely or you discover that the “alarm” was a power failure and the VoIP modem had no battery for back-up.  Other issues with VoIP for dialer communication are packet dropping and jitter. Think about it this way, the alarm sends a round of DTMF (4/2) or high speed tones to the central station, the VoIP service drops a packet or two of data or there is a brief echo and therefore the second round doesn’t match. You have no parity between the two rounds and the dialer hang up and tries again. Potential big problem. Avoid all VoIP for standard dialer communication. If a client is switching to Comcast or FIOS, offer (require) a cellular communicator. 
    Now that we’ve beaten that particular horse nearly to death, If any of you folks reading this would like to explore a lucrative RMR opportunity, please feel free to contact me personally at 855-864-7224 x 222 day or night or by e-mail at jwh@voipccg.com.  We are looking for SELECTED alarm companies in certain areas as we roll out our new Affiliate program. This is about business telephones not alarm systems. Each of your commercial clients has a business telephone system. Sometimes it’s old and cranky and expensive. Sometimes the monthly phone bill is outrageous. This is an opportunity staring the average security firm right in the face.
    Thanks Ken,
John Haenn
Concord Communications Group, Inc.