TOLLBRIDGE SPEECH QUALITY PROVEN COMPARABLE TO THAT OF PUBLIC SWITCHED TELEPHONE NETWORK
CT Labs Performed Voice-over-IP/Broadband Tests; TollBridge Solution also Ranked High in End-User TestsSANTA CLARA, Calif. - January 25, 2000 - TollBridge Technologies, the leading developer of high-quality voice-over-broadband solutions for a new generation of carriers, announced today that tests conducted in December 1999 by CT Labs found that TollBridge's Voice-over-IP (VoIP) solution offers excellent speech quality and performance. In the presence of typical network congestion, speech quality was comparable to that of the Public Switched Telephone Network (PSTN): Dual Tone Multi-Frequency (DTMF) transmission quality was exceptional, call setup/teardown time performance was excellent with no errors detected, and bandwidth use was also optimal. These tests are part of CT Labs' VoIP Certification Suite, developed to provide standardized performance measurements for voice gateways. In a separate study conducted among small-business IT professionals, users reported that the TollBridge system delivered voice quality comparable to that of traditional analog phones. When tested for voice quality, participants found no substantial difference in the TollBridge services vs. the traditional analog services. The study was conducted in a controlled environment with 83 percent of participation ranking the TollBridge VoDSL service as having very-extremely clear quality. "The results of these tests fully justify our belief that TollBridge offers by far and away not just the best voice quality for a gateway but the best possible voice quality, period," said Agnes Imregh, vice president of marketing at TollBridge. "Carriers can implement TollBridge-based VoIP solutions secure in the knowledge that they are offering their customers the same high voice quality they have come to expect from the PSTN." The Test Scenario
CT Labs used a test-call generator to generate a consistent flow of eight simultaneous test calls, the maximum capacity of TollBridge's TB50 Integrated Access Device (IAD). These calls were passed to the carrier-grade TB200 Local Exchange Gateway and then through routers and hubs to a WAN simulator, which simulated a variety of IP packet loss network conditions and performed comprehensive IP monitoring. The WAN simulator terminated into the TB50, which then terminated the test calls into eight analog phone lines. CT Labs evaluated the calls using an automated Perceptual Analysis/Measurement System (PAMS) that predicts the speech quality and listening effort for processed speech samples. Quality and effort were excellent under "no packet loss" test conditions. Under "packet loss" conditions (ranging from 1 to 5 packet loss), the TollBridge system performed very well compared to other gateway systems CT Labs has tested. CT Labs also tested the TB200 on the reliable transmission of DTMF digits in each direction of the call. DTMF transmission is a challenge for many voice gateways because DTMF signals are sent on the same audio passband as speech. Because many gateways try to encode speech information into as few bytes as possible, DTMF digits can be deformed. However, the TB200's performance in the clear channel mode was excellent. The call setup/teardown test determines how well a gateway handles the initiation and termination of calls when all channels are active and there are a relatively large number of calls per hour. Under these conditions, a call may either not go through or not terminate properly. CT Labs detected no failure of any TollBridge products under clear channel conditions. Achieving Voice Quality Through TollVoice Technology
The technical benefits of the TollBridge system are based on an architecture designed to efficiently convey toll?quality voice within the digital packet environment. At the core of the architecture is a suite of signal processing functions running on state-of-the-art digital signal processors (DSPs), providing audio compression, echo cancellation and network jitter buffering. TollBridge's selection of high-quality audio compression formats allows the user transparent access to all features previously enjoyed on conventional telephone service. Advanced echo cancellation techniques provide TollBridge technology users a clear connection free from echo, while an adaptive network jitter buffer queues voice samples off of the broadband network in a smooth, unbroken flow. About TollBridge Solutions
Designed to let providers bypass Incumbent Local Exchange Carriers (ILECs) to all deliver voice services over any broadband access technology, the TollBridge product set consists of three elements: - The TB50, an Integrated Access Device (IAD) that converts voice samples from multiple calls into packets and prioritizes voice and data traffic for transmission over any broadband access network;
- The TB200, a carrier-grade Local Exchange Gateway that translates packets back into voice and connects to Class 5 switches using the Telcordia GR-303 protocol and new, emerging protocols such as the Segment Interface protocol (SIP) and Media Gateway Control Point (MGCP);
- The TollViewTM Management Suite, a management system that includes a graphical Element Management System (EMS) for end-to-end configuration, troubleshooting, and performance management of up to 100 TB200 systems from HP OpenViewTM on SUN SolarisTM platforms.
About TollBridge Technologies
Founded in March 1998 and located in Santa Clara, Calif., TollBridge Technologies is the leading provider of voice-over-broadband solutions to a new generation of carriers. TollBridge solutions change the economics of delivering voice services by allowing carriers that own Class 5 switches to use broadband access technologies, such as DSL or cable, to bypass the incumbent local exchange carrier (ILEC) and deliver toll-quality voice and integrated data services. TollBridge and TollVoiceTM are trademarks of TollBridge Technologies, Inc. All other service marks and trademarks are the property of their respective owners. | 
