One of the most important aspects of VoIP service is the quality of your calls. Unfortunately, call quality relies both on your Internet connection as well as Verizon's service. To illustrate this, I used VoiceWing in two different locations. My main use was on my college campus Ethernet connection, which is known for high latency, even though we can have great download speeds. There is also the problem that during hours when many students are online, connection reliability takes a dramatic dip.
Fortunately, I found that the "Optimize your VoiceWing Phone Service" feature that I mentioned previously can do wonders for clearing up problems on a less-than-optimum broadband connection. The optimizing link performs a bandwidth test from your computer, which is assumed to be on the same connection as your phone, and reports the upstream and downstream bandwidth that it measures (Figure 5). It also provides a list of connection speed-based settings and a recommended setting based on the test results.
Figure 5: Optimization options
If your connection occasionally breaks up during calls or if the voice quality is not as high as you want it to be, you can go to this page and play with different settings. It's interesting to note that VoiceWing can work with allocated bandwidth as low as 22 kbps!
Fortunately, I was able to offset some of my voice quality problems by changing VoiceWing's Optimization settings. When I first started using the phone, the sound quality was a little worse than on my PSTN room phone. But after playing with the optimization a little, I was able to get the quality to a point where I really couldn't tell the difference between my room phone and the VoIP phone.
In the time I've used the service I have not had any dropouts and I heard someone break up only for a few seconds during a call. I was able to make calls to England with no more noticeable latency than using a standard phone and able to download files and browse online while talking on the phone with no dropouts. In general, I judge the quality of the calls to be acceptable, and not noticeably better or worse than with my standard line.
When I tried the phone adapter on a more reliable, higher-bandwidth 2.4 Mbit SDSL line, I immediately noticed a difference in call quality. I didn't change any settings, but the call was much more clear and sounded even better than my normal phone. The upshot of all this is that the Internet connection you're using does make a noticeable difference in call quality, but even an unreliable connection can still work well.