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Press Release: GL Announces Echo, Delay, and Voice Quality Analysis of Voice Calls in VoIP, TDM, 2Wire, and Mobile Networks

Gaithersburg, Maryland, USA - March 2, 2011 - GL Communications Inc. announced today the release of its newest Echo Measurement Utility Software (EMU) that measures Echo Path Delay (EPD) and Echo Return Loss (ERL) of voice calls. Speaking to reporters, Mr. Robert Bichefsky, Senior Manager, said, “Echo can be as simple as sidetone, or more complex such as line, and acoustic echo. The EMU when combined with GL’s VQuad™, Dual UTA, T1/E1 Analyzer, or Voiceband Analyzer, additional voice quality metrics such as round trip delay (RTD), voice quality, and noise can also be measured”.

He added, “A voice call may transit a variety of networks – Mobile, VoIP, TDM, and others. A typical call can have many of the following characteristics that can affect quality: narrowband (8 kbps) or wideband call (> 64 kbps), end-to-end digital but with D/D conversions (codec conversions), many D/A and A/D conversions, additive noise and/or background noise, speech level variations, variable delay, echo in the form of sidetone, line echo, or acoustic echo, signaling and voiceband conversions that affect DTMF, FAX, and MODEM transmissions,packet delay, loss, sequencing, and duplications”.

Mr. Bichefsky explained, “To provide a comprehensive assessment of voice quality irrespective of network type, GL has combined various tools together into one platform consisting of VQuad™, Dual UTA, USB T1 E1, and WEBViewer™. This platform provides the ability to make VoIP, TDM, and Mobile calls from any fixed or mobile location. All interface flexibility is provided (2Wire, 4Wire, VoIP, TDM, and Mobile) within the Dual UTA and USB T1 E1 Analyzer. In addition, VQuad™ provides algorithms for signaling, voice transmission, and voice quality assessment. WEBViewer™ provides the central point where voice metrics are stored and displayed through a WEB interface”.

“Recently, GL introduced Echo Measurement Utility (EMU) software within this architecture to assess sidetone, line, and acoustic echo and corresponding delays. EMU is an offline adjunct analysis application (under control of VQuad™) that compares the source and received files to determine echoes and delay of echoes. The EMU provides delay and ERL measurements for all detected echoes, along with an ‘ERL vs Delay’ plot where each echo is depicted within the plot. One can zoom-in on a particular echo to gauge overall echo impairments. In addition, the application includes signal graphs for source signal, received signal, error signal, and adaptive filter coefficients”.

Main Features:

  • Measures EPD in msec and ERL in dB
  • Compares source and received files to determine maximum of 4 echoes
  • Ability to automate the entire test process using VQuad™ scripting including sending the results to the central database for access via GL’s WEBViewer™
  • Detailed offline analysis
  • Supports Line and Acoustic Echo Modes
  • Graphically displays source signal, received signal, error signal, and adaptive filter coefficients
  • Allows zoom-in on each graph, and exporting snapshot of these graphs to a file for later analysis
  • Calculates adaptive filter coefficients and echo characteristics for the error signal
  • Speaker option to play the audio files (intrusive and non-intrusive)
  • Option to zoom-in on any particular echo to investigate further

About GL Communications Inc

Founded in 1986, GL Communications Inc. is a leading supplier of test, monitoring, and analysis equipment for TDM, Wireless, IP and VoIP networks. Unlike conventional test equipment, GL's test platforms provide visualization, capture, storage, and convenient features like portability, remotability, and scripting.

GL’s TDM Analysis & Emulation line of products includes T1, E1, T3, E3, OC-3, OC-12, STM-1, STM-4, analog four-wire, and analog two-wire interface cards, external portable pods, and complete system solutions. Capabilities include voiceband traffic analysis and emulation across all traffic types (voice, digits, tones, fax, modem), all protocols (ISDN, SS7, GR-303, Frame Relay, HDLC, V5.X, ATM, GSM, GPRS, LTE, etc.), and with capacities up to thousands of channels. Our newest products provide astonishing capacity and capture capability up to and including gigabit speeds.

GL’s VoIP and IP products generate / analyze thousands of calls and traffic simultaneously with traffic types such as frames, packets, voice files, digits, video, tones, noise, and fax. Almost all codecs are supported including G.711, G.729, AMR, EVRC-A,B,C, GSM, iSAC, and many more. Additional features include visual analysis, real-time listening, and recording. The product line also includes Ethernet / IP Testing capability that simulates and checks frame transport and throughput parameters of Ethernet and IP networks, including delay, errors and other impairments.

GL's Voice Quality Testing (VQT) product line complements all of GL's products. Using ITU-standard algorithms (PAMS, PSQM, and PESQ), GL's VQT provides a widely accepted solution for assessing voice quality in the telecom industry. Voice Quality Testing across multiple networks (T1, E1, T3, E3, OC-3, OC-12, VoIP, Wireless, and Landline) are all available.

GL’s Wireless Products perform protocol analysis and voice quality assessment on GSM, CDMA, UMTS, and LTE networks. Connections can be made to any wireless phone with automated call control, GPS mapping and real-time signal measurements.

GL’s Echo Canceller testing solutions provide the broadest range of simulation and analysis, including line and acoustic echo. GL’s compliance testing per G.168. G.167 and P.340 across TDM, IP, VoIP and Wireless networks is widely accepted in the industry.

GL’s wireless VQT solutions help assessing impairments to voice quality such as poor mobile phone quality, voice compression and decompression algorithms, delay, loss and gain in speech levels, noise, acoustic and landline echo, and other distortions are easily assessed and accurately measured.

GL’s Handheld data testers can test a wide variety of communications facilities and equipment including T1, fractional T1, E1, fractional E1, T3 and E3 modems, multiplexers, CSU, DSUs, T1 CSUs, DTUs, NTUs and TIUs and more. The testers provide convenience, economy, and portability for almost any interface, including RS232, RS-422, RS-530, X.21, T1, E1, T3, E3, and many others.

GL’s Network Surveillance and Monitoring products include Probes for TDM, IP, VoIP, ATM, and Wireless networks. An open standards based approach provides a scalable, feature rich, real-time access to network characteristics. Centralized or distributed access, efficient transport and database loading allow compatibility with 3rd party and standards based monitoring systems.

For more information about GL's complete line of products,


Shelley Sharma
Phone: 301-670-4784 ext. 114

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