Comcast's Digital Voice service was rated as having the best audio quality among nine voice services, while Time Warner Cable's took the No. 2 spot for reliability, according to a study of October calling data by Keynote Systems.
The Keynote study evaluates how end users experience the reliability and audio clarity of voice-service providers, based on data collected from calls made from residential locations in New York and San Francisco. The study compares the relative performance of AT&T landline service with Comcast Digital Voice, Time Warner Cable's Digital Phone and six broadband voice-over-IP providers — AT&T CallVantage, EarthLink trueVoice, Lingo, Packet8, Verizon VoiceWing and Vonage.
For the month of October, Comcast Digital Voice achieved a score of 901 out of 1000 points for audio quality, outdistancing Verizon VoiceWing (with a 609 score) and AT&T's landline service (506).
On reliability, the AT&T landline was tops with a 996 score, followed by Time Warner Cable Digital Phone with 925 and Verizon VoiceWing with 872.
Keynote named only the top three providers in each category.
The factors that contribute to Keynote's reliability ranking are: service availability, call completion, average answer time and dropped audio performance. This high-level ranking identifies which voice service providers are providing the most reliable end user experience. The audio-quality ranking is computed as an aggregate of the performance factors related to audio clarity and audio delay.
Keynote uses its Voice Perspective product to conduct calls and perform wave-form analysis of the results. Each call includes the transmission of a reference audio file specifically created with characteristics appropriate to voice audio-quality measurement.