VQT in TDM Networks

Overview

Voice quality is essential for all Networks as well as Gateways and Switches. Providing the mechanism for VQT over T1/E1 trunks is essential. The VQuad™ with TDM option provides the ability to perform manual or automated tests on the T1/E1 networks. The GL VQuad™ software combined with GL's Voice Quality Testing (VQT) software permits this desired VQT testing, yielding results that include PESQ (LQ/LQO/WB) and POLQA Mean Opinion Scores (MOS). These results provide an excellent overall measure of voice quality of the equipment under test.

The VQuad™ with TDM option includes the HD Universal Dual T1/E1 Card or tProbe™ T1 E1 Base Unit or Portable USB T1 E1 Analyzer for a truly portable solution. Using T1/E1 Analyzer, VQuad™ can generate and receive up to 8 simultaneous CAS, PRI ISDN, or No Call Control (NOCC) calls on either T1 or E1 trunks. The T1/E1 option includes a script based CAS State Machine for creating any desired CAS protocol. Included with the PRI ISDN are all variants associated with ANSI and ETSI specifications.

The GL’s VQT utilizes widely accepted algorithms to perform the voice comparisons, the Perceptual Evaluation of Speech Quality (PESQ LQ/LQO/WB’) per Rec. P.862.1/P862.2, the Perceptual Analysis / Measurement System (PAMS) per Rec. P.800, the Perceptual Speech Quality Measurement (PSQM) per Rec. P.861, and POLQA, Perceptual Objective Listening Quality Analysis, based on ITU standard, ITU-T P.863, is the successor of PESQ (ITU-T P.862). PESQ provides an objective measurement of subjective listening tests on telephony systems. PAMS predicts overall subjective listening quality (a human's perception of quality) without requiring actual subjective testing (a very expensive and time-consuming process). PSQM predicts subjective quality of speech codecs without requiring subjective testing. POLQA supports the latest HD-quality speech coding and network transport technology, with higher accuracy for 3G, 4G/LTE and VoIP networks. The VQT performs PESQ, PAMS, PSQM (+), and POLQA simultaneously, using two voice files (Reference File and Degraded File) and provides the algorithm results along with analytical results in both graphical and tabular format.