If your house is wired in a star configuration, smart home wirers do it this way, then disconnect just the home office from the rest and run a wire from the vonage box to the disconnected wires. Another option is to use the existing wire. Your phone only uses two wires, normally the center two, you colud use the outer two, then split it in you mom's office and have both there until the number is transferred. The length of time depends upon your current phone company. When I had mine transferred to SunRocket it took 29 days for the transfer and another 2 for AT&T to disconnect it.