To make your existing phone work with a VoIP technology, you will need an ATA box. By trying to force them to work, you will damage both the devices. That would not be possible as the connectors on the two devices are not of the same size or shape. However, you cannot just take your existing phone and plug it to your router or broadband modem. This means wires are involved here whereas with VoIP phones you can go wireless. On the other hand, traditional PSTN makes use of copper wires to transmit data and information. VoIP phones transmit information by the use of the internet.
Their usage is slightly different from VoIP phones. For most of you, it will come as good news that you can use VoIP technology in your existing phones.
