Another way to reduce bandwidth is to use sound suppression within the end-point equipment. Sound suppression sends traffic only when the volume exceeds a predefined decibel level. Keep in mind, though, that sounds are not limited to those emitted by the primary speakers. A passing truck, ringing telephones, background chatter and the beeps on your computer all can generate an audio signal of 64 Kbps. It is very difficult to eliminate these secondary noises entirely while preserving signal quality, though headgear with directional microphones can help.

If you can't reduce your traffic, you still can sidestep major bandwidth-utilization problems if you implement VoIP on a modest scale. It's highly unlikely that every user will be using the phone at once--realistically, usage is more likely to range between 10 percent and 50 percent during the workday. Furthermore, many calls will remain local within the floor or facility where they originate and not traverse the entire network. Your company may have statistics on usage patterns that can help you select the best areas for VoIP deployment.

VoIP at the Desktop
Bringing VoIP services to the desktop isn't easy, even without the bandwidth burdens mentioned above. And yet, integrating voice and data at the desktop has strategic advantages.

One popular way to implement VoIP at the desktop is to use software such as Microsoft Corp.'s NetMeeting or VocalTec Communications' Internet Phone. We don't recommend this path, however, because at this stage of their development, PCs have generally proved to be subpar for use as telephones, and many components would have to be added to improve them. Also, codecs can't run efficiently on a general-purpose PC that also must process interrupts, run programs and manage the operating system overhead. We have not yet found a software-based system that processes audio fast enough to be truly useful.

Remember, too, that software-based telephony gets cut off when the computer crashes, which is something PCs are still prone to do. If you can't take an sales order because your PC locked up, is the solution really cost-effective? At least with separate handsets, you can fall back on paper-based order entry in the event of a computer crash.