Press Release: GL Announces Enhanced
Echo Compliance Testing Software
Gaithersburg, Maryland, USA - April 19, 2011 - GL Communications Inc. announced today the release of its
enhanced Echo Compliance Testing Software - a tool to perform echo cancellation compliance testing automatically per
ITU G.168 specification. Speaking to reporters, Mr. Vijay Kulkarni, CEO of the company said, ďEcho is annoying. It distorts
intelligibility. Unfortunately, it happens in telephone networks, whether in the old PSTN, or in new Mobile and VoIP networks.
Echo tolerance is a function of delay Ė the more delay in the network, the more annoying the echo. It became a major
problem with the introduction of satellite voice networks in the late 70ís and 80ís. Equipment manufacturers were
addressing echo thru echo suppressors and newly developed echo cancellers. At that time, the CCITT (now called ITU),
began a standardization effort to specify the performance and testing of echo cancellers under the spec name ďG.165Ē.
It has since been superseded by G.168.Ē
He added, ďIn the last 12 years, ITU-T G.168 has undergone many revisions with greater and greater detail and
specificity. The latest version of G.168 is G.168 (2009). GL has been keeping up with the improved standards. Currently
there are 16 major tests with each test having many subtests and GL has wide gamut of tests supported and can be
viewed here: G.168 Tests.Ē
Mr. Kulkarni explained, ďEcho cancellers are sophisticated signal processing devices. Since the echo is somewhat a
replica of the original signal in the opposite direction, the EC attempts to subtract a ďscaledĒ version of the replica thereby
eliminating the echo. There are many subtleties to the EC process. For example, it should converge quickly, operate in
the presence of double talk, work for long or short delays, work for a broad range of signal levels, etc. As Mobile and
VoIP networks are also subject to echo, tests have been incorporated for these as well.Ē
He further added, ďSince the EC tests require varying levels of input signals, echo models, delays, and other
parameters, the permutations of tests becomes enormous and manual testing a virtual impossibility. GLís AutoECTest
software, however, simplifies the process by allowing the user to input all the variations desired. Literally thousands of
tests can be run overnight or over the weekend. The software is used by most all Echo Canceller (EC) manufacturers to
simplify the compliance testing of ECs.Ē
New Echo Canceller Tests Added
ITU G.168 (2009) introduced three new tests to its repertoire. They are:
- Test 12 - Residual Acoustic Echo Test - Many calls these days involve both handsets and speakerphones,
hence the need to test in the presence of acoustic echo in combination with line echo. This is NOT a test of acoustic echo cancellation,
but a test to ensure that line echo cancellation is not distorted by the presence of acoustic echo.
- Test 13 - Performance with ITU-T Low Bit Rate Coders in Echo Path (Optional) - The prevalence of low bit rate
codecs in mobile and VoIP networks presents the possibility that such paths may exist in the echo path. In this test ECs are tested to
ensure that any degradation is within limits.
- Test 16 - DTMF Transparency Test -Generally DTMF digits are present on local loops, but it is possible that a
Gateway or an Interactive Voice Response (IVR) system may also require them. In such cases, ECs, should not degrade the transmission
of DTMF digits any more than without ECs.
The above tests have been incorporated into the latest release of GL's AutoECTest Software,
a program that permits automatic testing of the full complement of G.168 tests using GLís T1 E1 Analyzer products.
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.
GLís 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.
GLís 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.
GLís 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
GLís Echo Canceller testing solutions provide the broadest range of simulation and analysis, including line and acoustic
echo. GLís compliance testing per G.168. G.167 and P.340 across TDM, IP, VoIP and Wireless networks is widely accepted
in the industry.
GLís 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.
GLís 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.
GLís 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
For more information about GL's complete line of products,
Back to Press Releases Index Page
Phone: 301-670-4784 ext. 114