The State of VoIP
Just a few years ago, voice over IP (VoIP) was considered a novelty, but with annual growth rates of more than 20 percent, adoption of this service is widespread throughout the business and private sectors.
Many experts believe that wide frequency response is essential to intelligibility in voice communications. For example, when you look at the differences between similar-sounding words such as “sailing” and “failing,” the sound component that provides the distinction between these two words is the sibilance in the ‘s,' which is found entirely in frequencies above 3 kHz.
Clearly distinguishing between consonants could make all the difference in understanding someone's intent during a call. (See wideband versus narrow-band diagram, left.) In today's business climate, where many different accents from across the globe often interact daily, the narrow bandwidth of dialup lines can greatly hinder the ability to conduct business due to the reduced intelligibility inherent in those types of calls.
Another advantage of the new standardization on SIP and G.722 is the ability to use different vendors' telephone instruments on an IP PBX. In circuit-switched Public Switched Telephone Networks (PSTN), most PBX systems are proprietary, and it's next to impossible to operate a different vendor's device on the PBX. Anyone who has tried to install a dial-up telephone interface in a conference room has run up against this difficulty; it is usually necessary to request a “fax line” or analog-simulating extension in order for the telephone interface to operate. Not so with a SIP-based G.722 IP PBX.EQUIPMENT QUALITY
Wideband voice calls over IP are only possible if every component of a call is set up for G.722 operation. This includes the VoIP phones, the IP PBX, the service provider's trunking system, and the equipment at the far end of a call. If any element of the VoIP system is limited to narrowband operation, the result to users will not be a “high definition” experience.
Equipment quality also comes into play when considering a wideband VoIP communications system. Just as differences exist between HDTV sets, VoIP handsets and conference phones can vary in quality, and a phone promoting wideband audio may have less-than-ideal sound simply because of poor quality components used in its manufacture.
Aras says the phones not only need the appropriate microphone and electronics to send wideband audio, they must faithfully reproduce it on the loudspeaker or handset.“It's not just the actual telephones, either,” says Aras. “The voicemail systems, the IP PBX, message centers, etc. all need to be considered. Every component of the system in the enterprise or facility should support wideband frequency response in order to be a complete system to the customer.”
From a systems integration standpoint, Aras believes there is a great deal of synergy between the VoIP trend and enhanced communications that can be installed throughout an enterprise. “Enterprise customers are interested in deploying IP based technologies not just for videoconferencing, but for daily use as well,” he says. “Integrators can take advantage of this level of interest to recommend high definition communications systems that will provide maximum customer satisfaction no matter whether a user is in the office or the boardroom.”
Elaine Jones is principal of Elaine Jones Associates, a marketing and public relations firm in Salt Lake City. She can be reached at firstname.lastname@example.org.