Belkin F1PI241ENau User Manual - Page 5

Product Overview Voice over IP (VoIP) An Introduction Using Voice over IP (VoIP), instead of making calls over the regular telephone network, calls are made over computer (IP) networks, either through your Internet Service Provider's connection or through your local network. Calls made are generally cheaper than traditional calls. The basic steps involved in VoIP include the conversion of an analog voice signal to digital, the encoding and then compression of the signal into Internet Protocol (IP) packets. The VoIP Router is equipped with a digital signal processor (DSP), which segments the voice signal into frames and stores them in voice packets. Using the industry standard codecs, G.711, G.723.3 and G.729, these packets are encoded. These IP packets are then transmitted in accordance with International Telecommunications Union specification SIP over the Internet to their destination where the process is reversed. Advantages of Using VoIP The main advantage of VoIP over the traditional Public Switched Telephone Network (PSTN) is the ability to make low-cost calls over the IP network. One of the greatest benefits is cheaper long distance calls. Past Problems Internet-based telephony has been around for years but, until now, has not reached the mainstream market. Products with a true cost-saving advantage over standard telephones do not have comparable call quality. Users experience a prolonged delay making conversation difficult. Call-completion rates are very low due to firewalls and the use of Network Address Translation (NAT), which renders over 50% of residential computers unable to communicate with traditional VoIP software. The user interface is complicated, and requires substantial configuration and technical skills. 6 Product Overview 1 Recent Developments Even as streaming audio and video over the Internet became common, VoIP quality was still sub-par. What, you may ask, is the reason for this? While 2 it's relatively easy to convert a song or even a video into IP-based packets and have it arrive in decent shape, the Internet was not designed as a two- 3 way street, i.e., to support two-way communications as in your typical conversation. Early VoIP calls were much like walkie-talkie speech, halting and unsynchronized. A common trick was to let the other speaker know you had 4 finished talking by ending your statement with the word "Over." For example, "How are you today? Over." "Not too good, I think I've the flu. Are you busy? Over." 5 6 This method was effective, but hardly conducive to a comfortable conversation! Therefore, substantial cost savings, although attractive, were not enough to make up for unacceptably poor call quality. Now, however, thanks to dedicated 7 hardware processing and protocols like Session Initiation Protocol (SIP), VoIP can be as smooth as a session that uses the regular telephone network, greatly increasing its appeal. Equally as important to VoIP's recent surge has been the widespread adoption of broadband in both homes and businesses, which delivers the bandwidth required to come close to PSTN quality. Features and Benefits NAT also enables multi-user Internet access via a single user account, and virtual server functionality (providing protected access to Internet services such as Web, FTP, email, and Telnet) VPN pass-through (IPSec-ESP Tunnel mode, L2TP, PPTP) User-definable application sensing tunnel supports applications requiring multiple connections easy setup through a web browser on any operating system that supports TCP/IP compatible with all popular Internet applications. VoIP Features and Benefits Full Session Initiation Protocol (SIP) support Voice Activity Detection (VAD) conserves bandwidth Quality of Service (QoS) provides superior voice quality 7 section