In a perfect world this might work if telco service is not dicsonnected. However there is roughly 48 VDC from the both the telco service as well as from the the VOIP ATA. If the house wiring should somehow have gotten reversed in the wall outlet, you effectively have opposite polarities bucking each other - a short. In other words please disconnect the telco service first.
The only safe way is to disconnect the reqular telco lines at the outside entry box. Just unplug the Rh-11 connedtion there. Even then I always plug a line cord into an inexpensive wall surace mount outlet and plug the other end into the house wiring. Use a voltmeter to check to be sure no sneak voltage. Check both lines. If no voltage is present, then use a line cord to connect line 1 of the VOIP ATA to the house wiring. If a VOIP FAX line has been obtained, purchase a line splitter from Radio Shack or many other places. Plug it into the house wiring outlet and then plug the line cord from the line 1 of the VOIP ATA into line 1 of the splitter. Check to see if you are getting dial tone in your house telephones. If not move the line cord to the other input of the splitter. If this works, then connect line 2 from the ATA into the other input of the splitter. Dial tone should be heard there - if it is being drawn form the ATA in earlier checks.
We have excellent electrical power in this area and seldom lose it - which would lose you VOIP telephone service. If you install a fairly inexpensive no-beak power supply to provide power to the ATA and cable modem, it will provide the needed power for telephone service as long as the battery in the no-brak supply lasts.
Has anyone tried the Broadband phone service, "Vonage" or another one like it? I am wondering how good it really is and what all you need to get it going if you already have a broadband connection.
Thanks,
Dave

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