VoCable

About

                Voice (and fax) service over cable networks is known as cable-based Internet Protocol (IP) telephony. Cable based IP telephony holds the promise of simplified and consolidated communication services provided by a single carrier at a lower cost than consumers currently to pay to separate Internet, television and telephony service providers. Cable operators have already worked through the technical challenges of providing Internet service and optimizing the existing bandwidth in their cable plants to deliver high speed Internet access. 

Voice Activation Detector

        This monitors the received signal for voice activity. When no activity is detected for a specific period of time, the software informs the IP. This prevents the encoder output from being transported across the network when there is silence so as to save the bandwidth. This software also measures the idle noise characteristics of the telephony interface. 

PCM Interface (Pulse Code Modulation Interface)

        This interface receives pulse code modulation (PCM) samples from the digital interface and forwards them to the appropriate DSP software modules for processing. 

Embedded Software Architecture

        Texas Instruments and its subsidiary, Telogy Networks, have developed one implementation of embedded VoIP software for cable-based IP telephony. The software supports cable modems and BTIs (up to four ports), as well as the telephony gateway (up to several thousand ports), at the cable head end. The software supports MGCP (Media Gateway Control Protocol) as well as the session protocol (SIP). The basic purpose of the two protocols, which is to process packetized voice traffic, is the same. However, the software supports both because standard bodies are divided as to the relative merits of each. 

Conclusion

        With the merging of telecom carriers, cable operators, and Internet service providers (ISPs), most experts agree that convergence is not merely a trend but an inevitability. The potential cost savings, consolidated billing, streamlined network management, and overall convenience are too compelling for service providers and customers to ignore.