Voice over frame relay vs VoIP?

What is the difference between voice over frame relay and voice over IP? These are two completely different technologies. Voice over frame relay (VoFR)is the packetizing of voice to transmit over leased lines to a frame relay cloud. Once you order this service, you are provided with enough bandwidth to access frame relay packet networks that are optimized to carry both voice and data. Using Frame relay networks to send voice can cut down on the cost of long distance dialing since access to the cloud is via leased line. Voice over IP (VoIP) can be sent over VoFR networks. VoIP is a technology devised to utilize your existing IP infrastructure to carry voice. This can be accomplished by using intelligent phones that have both a MAC address (NIC card) and an IP address. Your voice is encapsulated into an IP packet and transmitted to the PBX. This allows your phone to be identified by an IP address instead of a phone number. The reason behind this is so that like a computer, a phone can be relocated easily to any location without the need for patching or PBX reprogramming. Essentially, since the PBX now communicates to the phone using IP, it will know what phone number to send and receive voice information regardless of location.