

As far as the 848 is concerned, VoIP (Vonage, etc.) and cable phone service are just sources
of dialtone. They don't require anything special in the 848 -- just plug in and start talking.
Here's what Cablevision says (other cable companies say pretty much the same thing).:
"Customers using Optimum Voice as a connection between their home security system and central
station monitoring are responsible for testing their system with their alarm company at the time of
installation and on an ongoing basis.
Additional Information on Home Wiring:
Your Optimum Voice modem is electrically powered. In the event of power outages, the modem,
including all phones and services connected to or powered by it, will not work. Power outages will
disrupt Enhanced 911 service, and the use of Optimum Voice as the connection between your home
security system and central monitoring services. A back-up battery can be purchased to supply power
in the event of a power outage.
Optimum Voice does not offer a wire maintenance plan. You are solely responsible for maintaining all
wire and phone jacks within your home. We will be happy to troubleshoot and fix reported problems for
a service charge. Optimum Voice will waive the service charge for inside wire repair and maintenance
work for the first 30 days after a professional installation of the service.
Cablevision does not support the use of Optimum Voice with emergency medical alert systems.
Cablevision does not guarantee that Optimum Voice will function with Key systems and PBX systems
and will neither connect to such systems nor provide technical support for the connection to such
systems."
VoIP & cable installation
TAWsystems.info