Cisco’s Voice Over IP (an early example)

Cisco 3600 series routers^† to carry live voice traffic (e.g., telephone calls and faxes) over an IP network. (This was the first of the Cisco routers to support VoIP.)

They state that this could be used for:

Toll bypass
Remote PBX presence over WANs
Unified voice/data trunking
POTS-Internet telephony gateways

Uses Real-Time Transport Protocol (RTP) for carrying packetized audio and video traffic over an IP network.

^† The Cisco 3600 series was introduced in 1996 and their end of life was 31 December 2003. So this represents ancient history, but illustrates the many issues that have to be addressed by a gateway in order to support existing users and devices.

Transcript

[slide41] Now, a long time ago, Cisco introduced the 3600 series of routers. They were introduced in 1996. They were already obsolete by 2006. But they built cards for them so that they could support voice over IP. Both client side and connecting to telephony lines. And they said it could be used to support toll bypass. So instead of making toll calls, you would send it tunneled over the network. Or remote PBX presence. Or unified voice and data trunking. Or plain old telephony to internet telephony gateways. And they used RTP. They carried the packetized audio and video across the IP network.