Teraquant is the foremost expert on POLQA and PESQ perceptual voice quality testing, and MOS in North America. We partner with Opale Systems (formerly Malden Electronics Ltd) to make accurate measurements in the lab, bringing those measurements to the field and drive testing. We also analyze speech quality in operational networks, in enterprise networks and for service providers, drilling down to determine the root cause. We collaborate closely with research labs worldwide working on next-generation voice quality and intelligibility standards.




MultiDSLA is a standards-based Active Analyzer for Voice Quality Testing and Speech Performance Assessment. It utilizes PESQ and POLQA® measurements which are international standards widely accepted by the VoIP industry. MultiDSLA delivers unparalleled accuracy and repeatability, a complete set of voice measurements, plus a comprehensive array of measurement endpoints that allows for performance testing between any endpoint in analog, digital, mobile or IP domains. The MultiDSLA is approved for testing of cellular phones, desk phones, analog (POTS) phone lines, ATA’s, PC sound cards (for soft-phones), and audio streaming devices, as well as for End-to-End voice services over IP and wireless networks.

Teraquant installation and training for Opale Systems products is customized to meet your specific learning objectives.

Discuss Your Requirements
MultiDSLA Actively Tests Devices and E2E Network Quality
  • Analog and Cellular Nodes (Mobile Phones & Tablets)
  • VoLTE and VoIP Nodes (Softphones & VoIP Endpoints)
  • ISDN/TDM to VoIP Gateways
  • Audio Streaming
MultiDSLA Measurements Made
  • Perceptual Voice Quality or Speech Clarity (POLQA, PESQ & MOS)
  • Audio Streaming Integrity (ASI)
  • Voice power level
  • Echo
  • DTMF
  • One-way & E2E delay/latency
  • Frequency Response NB/WB/SWB/FB
MultiDSLA offers smart analytics and key performance indicators to help you identify the root cause of distortions in the degraded voice signal:
  • Network Impairments: one-way delay, packet loss, jitter buffer behavior and echo.
  • Speech and Noise levels.
  • Codec distortion.
  • Voice Activity Detector (VAD) performance.
  • Call setup analysis.
  • DTMF sequences.
  • And much more!



  • Simultaneous control of many nodes.
  • Flexible automation system.
  • POLQA®, PESQ and E-Model Voice Quality.
  • Root cause analysis.
  • Speech level, noise, delay and echo measurement.
  • DTMF sequence generation and analysis.
  • Conference bridge testing.
  • Speech recognition.
  • SLA management and alarms.
  • Summary reports.
  • Pass/Fail criteria.
  • Remote access open API.


Analog and Cellular Nodes are used for testing involving cellular phones, desk phones, analog (POTS) phone lines, ATA’s, PC sound cards (for soft-phones), and audio streaming devices.

VoLTE and VoIP SIP Nodes — These nodes utilize VoxPort Packet (VPP), a new-generation SIP endpoint. it provides VoIP signal generation and measurement capabilities within the IP domain, or between the IP domain and the analog domain. Managed by MultiDSLA Controller software, VPP brings standards-based voice-quality testing methods to VoFi, VoIP or VoLTE networks.

ISDN and TDM DSLA Nodes — ISDN BRI and PRI/E1/T1 nodes consist of PCI/PCIe cards and a Windows client application. MultiDSLA Controller uses these interfaces to perform tests on any or all TDM time-slots, simultaneously if required. ISDN BRI and PRI/E1/T1 nodes connect digitally into a TDM telephone network. Both ensure that no noise is picked up in the analog access network and that echo conditions are controlled on the testing side. Comprehensive implementation of ISDN signaling protocols, including all international ISDN variants and QSIG, ensure easy integration with all networks.

Audio Streaming Nodes — The Audio Streaming Integrity (ASI) metric is an option to the Opale MultiDSLA test system. ASI detects, qualifies, records and logs breaks or distortions in audio continuity over any test period, providing a cumulative count plus the duration and timestamp of each anomaly.


Perceptual Objective Listening Quality Analysis (POLQA®) is the latest objective measurement for speech quality standardized in 2011 (ITU-T P.863). POLQA is an enhancement to the PESQ algorithm (ITU-TP.862) introduced in 2003 which allowed perceptual speech quality measurements to become a mainstream method to evaluate end-to-end speech clarity. Perceptual speech quality measurements are needed when speech is compressed such as in a voice codec (eg: G.729, G.711, G.726, etc) and then transported over wireless or IP-based networks.


The main driver for the new POLQA standard was wideband telephony – sometimes called HD-voice – as defined by the G.722 and G.722.1 (wideband AMR) standards. In addition, POLQA analyzes speech to the limit of the human ear (20 kHz analog bandwidth). The POLQA algorithm supports measurements from the narrow band (NB – 300–3,400Hz, or traditional PSTN telephony), wideband (WB, up to 7kHz), super-wideband (SWB, 50–14,000Hz) and Fullband (FB, 50–24,000Hz).


  • Accuracy avoids the cost of chasing and repairing a problem which has no impact on quality or user experience.
  • Accuracy allows you to pin-point the real cause of bottlenecks in your system.
  • Accuracy prevents you from failing a good product.


  • Voice Codec performance.
  • Compare different algorithms and implementations.
  • Know bandwidth required if you are to achieve a given level of voice quality.
  • Packet Loss Concealment mechanisms.
  • Determine capacity of devices such as gateways sharing DSP resources between voice streams.


  • Isolate network elements contributing to poor voice quality.
  • Baseline current voice quality to set realistic goals for VoIP migration.
  • Monitor voice SLA’s.
  • Provide objective acceptance criteria.
  • Eliminate good networks from bad networks.


  • Handsets and Mobiles for cellular, Wi-Fi and VoIP.
  • VoIP gateways.
  • Any device with a voice codec (eg: VoIP endpoint or transcoder).

For further information, click here to request more information.

You might also want to check our whitepaper A Practical Guide to Troubleshooting Poor Speech Quality — End-to-End.


  • Opale Systems produces the most accurate measurement of PESQ (ITU-T Recommendation P.862) and POLQA® (ITU-T Recommendation P.863) available worldwide today. They also provide the most accurate measurement of one-way delay for a voice path available, based on the delay of the audio and not just delay of packets across an IP network.
  • Malden, now Opale, was the first to launch the new POLQA standard on a test platform when it was introduced on the MultiDSLA speech-quality tool in 2011.
  • Opale Systems MultiDSLA also provides unique analytics, drilling deep into the POLQA metrics to provide insight on what is going wrong when you get poor scores.
  • The POLQA algorithm was introduced to deal with some of the weaknesses inherent in PESQ, as well as to address Wideband telephony, or HD voice (ie: voice communication above 3.4kHz).
  • You should consider testing with POLQA if you:
    Are using either Wideband or Super-Wideband codecs (7–24kHz analog bandwidth) — sometimes known as High Definition (HD) audio.
    Use codecs that employ time-warping (eg: CDMA or EVRS).
    Work with CDMA terminals and/or networks.
    Have a network that uses AMR codecs.
    Are testing through acoustic interfaces.
    Are concerned about voice quality enhancement and noise reduction devices/processes.
  • The principle is similar to PESQ — comparing the clean reference file with the degraded file from the network — but the test methodology is different. POLQA has two models, one for Narrowband and one for Super-Wideband. The Super-Wideband model can be used for any network from 300–24,000Hz analog bandwidth. The Narrowband POLQA algorithm is for legacy telephony on networks up to 3.4kHz, and provides compatibility with PESQ NB and narrowband subjective test data.

MultiDSLA makes it easy to use POLQA. Malden’s long experience in the application of speech quality metrics, inherited by Opale, ensures that you will be getting useful results as soon as the option is enabled on your MultiDSLA system.


For continuous measurements in operations, automation is built-in. Software or hardware probes can be deployed worldwide, with results gathered and graphs generated centrally.

Discuss Your Requirements

If you want to know more about making accurate POLQA measurements, click here for more information, or call us at +1 (719) 488-1003.

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