What is the difference between VoIP and Digital Telephony?
Digital is whatever which is not analog. In the form of 1's and 0's. So what you basically do is digitize the analog signal [voice].
VoIP is also in digital form but in VoIP voice is carried in IP packets through the network.
Digital telephony the voice traffic is not in form of IP packets.
VoIP =Voice Over data networks (IP traffic)
Digital (Traditional TDM or legacy PBX with propietary protocols)
Bunch of info in the net