How does an expandable cordless phone work?

I have Vonage, so I only have one phone jack to plug in a phone. Does a cordless expansion phone have to hook into some kind of jack or do you just have to plug the second base unit into a power outlet? How does that work? How close do the 2 units have to be to each other?

Expandable phones work by having one main unit plug into the phone jack and the rest use it's connection much like wireless computers use WiFi connections. The additional handsets usually have a "base" that plugs into an electric outlet for recharging the handsets. Handsets also have to be registered with the main unit (at least for the panasonic phones I have). Depending on the model, your number of maximum handsets will vary. You should decide how many handsets you need and then find the model that fits your needs (i.e. is compatible with Vonage or VOIP and can be expanded to the number of handsets needed). Also review costs including the cost of expanding to additional handsets.

The best solution to your answer is a cordless phone system where you can have many handsets (typically up to 4 handsets, but sometimes up to 8 handsets) that all communicate with one base unit. The base unit is plugged into the phone jack and power, and all of the handsets can communicate on the phone or with each other.

Panasonic makes several expandable handset systems, like the KX-TG4324B (http://www2.panasonic.com/consumer-electronics/shop/Phones-Fax/Telephones/5-8-GHz-Phones/model.KX-TG4324B_11002_7000000000000005702). As you can see, this system has one base unit, which plugs into your Vonage box, and four handsets that can be placed in other rooms. All of the handsets can communicate with the base unit (and, thus, Vonage) and with each other (intercom).

I feel that these systems, or similar systems from other manufacturers, would best address your needs.