1950
Epoch-making legislation by the Danish parliament: hearing examination and hearing aids free of charge for all

Early 1950s
Poul Madsen buys a radio shop in Odense, Denmark, and later starts making audiometers as a sideline for ENT physician Ole Bentzen

Late 1950s
Madsen starts up his first company, AMPLEX, in Odense, manufacturing the OB 1 audiometer named after Ole Bentzen

1960
Dr. K. Terkildsen of the University Hospital of Copenhagen and Engineer Scott-Nielsen of the Hearing Center in Copenhagen initiate collaboration with Poul Madsen on an impedance bridge

1960
Poul Madsen sells Amplex and moves to Copenhagen to found Madsen Electronics. Krogsø rename the former company Kamplex.

1960
Madsen Electronics introduce TAN 60, a small portable diagnostic audiometer and OB 60, a new clinical audiometer

1961
Introduction of the first commercially available electro-acoustic impedance bridge, the Madsen ZO 61 (purchased by, among others, James Jerger)

Mid-1960s
Both Madsen Electronics and KAMPLEX offer a full product line of both portable and stationary audiometers and impedance bridges

1960-70
Madsen, Terkildsen and Scott-Nielsen travel the world holding Impedance Schools

1969
Poul Madsen moves to Canada and founds Madsen Electronics, Inc., in Toronto

1969
Using the ZO 70, Jerger and his group at Baylor tested a consecutive series of about 400 patients and published the results in a seminal paper entitled "Clinical Experience with Impedance Audiometry"

1969
Madsen Electronics start collaboration with Scott-Nielsen and Osterhammel on the world’s first commercial ABR system

1971
Günter Hortmann founds HORTMANN in Metzingen, West Germany

1971
ERA 70, the world’s first commercial ABR system is presented by Madsen Electronics

1972
Jørgen Jensen and Arne Poulsen buy parts of the Kamplex estate and found Danplex in Odense, Denmark

1973
Danplex launches the ZA20, the world’s first portable electroacoustic impedance meter

1974
Madsen Electronics introduces the ERA 74 with digital calibration memory, post-stimulus delays for the elimination of artifacts in ABR recordings (includes data interface communication port)

1974-84
Madsen ERA Schools are held throughout the world

1975
HORTMANN presents the world’s first air caloric irrigator, the AIRMATIC

1976
Danplex introduces the world’s first digital audiometer, the AS20

1977
Delmar Bloem and Robert Simenson meet at FMC Corp. in Chicago

1977
Steen Rasmussen leaves Madsen Electronics and founds Rastronics in Lynge

1978
HORTMANN moves to Neckartenzlingen, near Stuttgart

1979
Dr. Hallowell Davis coins the term ABR

1980
Danplex merges with DanaMedica; Gunnar Klansø becomes CEO

1981
ICS Medical founded in Chicago, U.S.A., by Delmar Bloem and Robert Simenson

1981
Danplex introduces the first custom-made ITC hearing aid in Denmark

1981-82
Madsen launches a computerized clinical audiometer (OB 802/822), which included a number of firsts: two-way data communication interface, fully electronic attenuators, electronic calibration memory and interlocking stimulus and masking

1982
Rastronics presents the world’s first REM system CCI-10/1 at UHA in Germany and ASHA in the USA

1982
HORTMANN introduces the SH 221 BERA system

1983
In August, sales of the Rastronics CCI-10/1 kick off in the USA

1983
Rexton Danplex launches the Tymp 82 fully automatic tympanometer; hundreds of units sold through HORTMANN in Germany

1984
Presentation of the first computerized impedance bridge, the Madsen ZO 174, using a video monitor for the display of the test results

1984
Steen Rasmussen publishes the paper “How insertion gain measurement can take the guesswork out of hearing aid fittings” in Hearing Instruments, January

1985
The staff and friends of Madsen Electronics celebrate the company’s 25th anniversary in Herlev under the banner ”Helping the world to better hearing”

1985
ICS Medical introduces MASTR, the first commercial computer-based system for electronystagmography (ENG)

1985-86
Rastronics holds REM Schools all over the USA and featuring a Faculty of world famous speakers: James Jerger, Charles Berlin, E. Robert Libby, Jerry Northern, Mead Killion, Jerry Popelka, and Earl Harford

1986
The Madsen MTA 86 automatic screening audiometer improves industrial screening by combining rapid, automatic testing of both ears with printout of results

1986
Introduction of the first Madsen Electronics real ear measurement system, the IGO 1000, which featured a color monitor and multilingual, menu-driven user interface. The system could be upgraded with the addition of a hearing aid test box for hearing testing, the HAT 1000

1987
Claus Bak Petersen and Ivan Ring Nielsen found Technodata as a consulting company

1987
Rexton Danplex is acquired by Siemens; development of the PMC. The first interface box for programming hearing aids

1987
Rastronics win NAL tender for 180 REM systems leading to design and launch of portaREM-20

1988
Madsen Electronics presents the first softkey-driven diagnostic audiometer Midimate 602 featuring user-programmable tests, non-volatile calibration memory, fully click-free attenuators, multi-lingual display

1988
Rexton Danplex introduces the highly successful HandTymp, a handheld middle-ear screener featuring infrared data transmission to printer. Also the Tymp 83 and Tymp 87

1988
Poul Madsen sells the Madsen Electronics A/S to an investment company

1989
The Micromate 304 replaced the widely used range of Madsen screening audiometers and featured battery or AC operation

1989
Madsen Electronics collaborates with an Italian software developer to develop audiological software. Audiogram threshold transfer from Midimate to PC demonstrated to enthusiastic audience of American SIDs in Herlev

1989
Introduction of AUDIOCOM, the first commercially available audiological software program, with its own database for audiometric and impedance measurement data

1986-89
Madsen Electronics holds Insertion Gain Schools throughout the U.S. and Europe

1989
Steen Rasmussen sells 80% of Rastronics stock to Cabot Corp.

June, 1990
Madsen Electronics is purchased by GN Danavox, a leading manufacturer of hearing instruments, and a member of the Great Nordic group

1990
Madsen immittance equipment had been hitherto developed and manufactured in Toronto. Following the sale of the Canadian subsidiary, all immittance know-how was transferred to Herlev resulting in the development of the Zodiac 901 middle-ear analyzer

1990
AUDIOCOM is replaced by MateBaseI developed by Madsen Electronics

1991
Steen Rasmussen sells rest of Rastronics stock to Cabot; Rastronics is purchased by Danplex

1991
Danplex conclude OEM deal with Starkey for supply of REM equipment. Deliveries at the rate of approx. 400 units per year

1992
Technodata and GN Danavox found AuditData as equal shareholders

1992
The Madsen Electronics sales office in Toronto is closed down and operations moved to the premises of GN Danavox Inc. in Minneapolis

1992
At AAA, Madsen audiometers and impedance bridges feature "connectivity" interfacing with PCs and other Madsen instruments

1993
Featuring a large display and wide-ranging routing possibilities, the Madsen Orbiter 922 clinical audiometer replaces the best-selling OB 822 (over 4,000 units sold world-wide) – the 922 also allows direct control of CDs for presenting speech materials

1993
Several years collaboration between the University Hospital of Copenhagen and Madsen Electronics on an Otoacoustic Emissions project bear fruit and the Celesta 503 is launched

1993
Madsen Electronics and GN Danavox move to new premises in Taastrup, near Copenhagen, allowing the synergies between the two companies to flourish

1993-94
Introduction of the HI-PRO hardware interface box – a successful attempt to get manufacturers of hearing instruments to use the same interface for their programming software. Over 30,000 units manufactured to date

1993-94
The same period sees the launch by HIMSA of the NOAH software standard – Madsen Electronics commits to supporting this standard and implementing a NOAH interface in all equipment (except screeners)

1994
ICS Medical launch the CHARTR system, which combines ENG and VNG with the option of rotary vestibular testing (RVT)

1995
At AAA in Dallas, the PC-based Aurical is demonstrated for the first time. Combining audiometry with NOAH-based hearing instrument fitting and testing, this system goes on to sell in excess of 10,000 units and becomes the industry’s gold standard

1995
Siemens sells Rexton Danplex to Gunnar Klansø. Development starts on UNITY system for Siemens

1995
Madsen Electronics continues to innovate by introducing a diagnostic audiometer featuring automatic screening and a removable memory card for data storage (Voyager 522)

1996
Rexton Danplex is renamed Danplex A/S. Stefan Bengtsson and Erik Køster each buy 15% of Danplex stock.

1997
Michael Brock is appointed president of Madsen Electronics

1997
ICS Medical add Windows®-based evoked potential testing to the CHARTR platform

1997
Danplex hearing aid division sold to Siemens. All hearing aid activities cease

1998
The success of the Aurical has made Madsen Electronics the supplier of choice for a growing number of hospitals and some of the world's largest chains of hearing aid dispensers; Amplifon gives several orders totaling more than 1200 systems, the largest single deal in the industry to date

1998
Madsen Electronics changes corporate identity and implements the new slogan “The Computer People in Audiometry”

1998
Danplex make new OEM agreement with MedRx for supply of OtoWizard. Introduction of the Millennium, a portable hearing aid test and fitting system incl. audiometer and CD-ROM drive

1999
Launch of the Danplex DA65 diagnostic audiometer

1998/99
Madsen Electronics embarks on a long-term alliance with German manufacturer Fischer-Zoth and begins global marketing of the Echo-Screen infant hearing screener under the Madsen label

1999
ReSound Corp. and GN Danavox merge to form GN ReSound

1999
ICS Medical move into spacious new premises at Schaumburg; enter into an informal cooperation with GN ReSound to build MADSEN Capella OAE/Tymp technology into the CHARTR platform

1999
In acquiring Danplex, GN ReSound signals a new strategy aimed at creating the world’s largest manufacturer of instrumentation for auditory diagnostics and hearing instrument dispensing. Danplex has previously acquired the Rastronics brand and product line

2000
The acquisitions of HORTMANN and ICS Medical add balance assessment and ABR measurement to the portfolio; a busy period of transition and integration begins

2000
TechnoData sells its holdings in AuditData to GN ReSound

Jan. 1, 2001
The Madsen, Danplex, Rastronics, ICS Medical and Hortmann brands are assimilated into one entity named GN Otometrics

April 1, 2001
GN Otometrics moves into new headquarters near GN ReSound in Taastrup.

May 1, 2001
GN Otometrics, North America, moves into new headquarters together with GN ReSound in Bloomington, Minnesota

2002
Work starts on a massive new immittance development project nicknamed “Sophie”

March, 2002
The AccuScreen infant screener, which combines ABR and OAE, is launched at GN Otometrics’ first Global Sales Meeting in Helsingør

2002
Internal brand synergy sees the successful repackaging of the DA65 diagnostic audiometer as the Itera, a masterpiece of ergonomic and aesthetic design

December, 2002
Robert M. Simenson retires from ICS Medical

2003
Launch of PediHear website for advancing pediatric hearing by providing online resources, located at www.pedihear.com

2003
The OTOflex 100 handheld immittance device is unveiled to SIDs at AAA in San Antonio, a wireless revolution begins

2003
AuditData joins GN Otometrics in the Taastrup HQ; Gunnar Klansø and Delmar Bloem retire

2003
Launch of the education-oriented website, Bsure for advancing balance assessment located at www.bsure4balance.com

2004
OTOflex 100 is launched globally and is one of the stars of the show at AAA in Salt Lake City

Summer, 2004
Michael Brock resigns as president and Søren Holst ushers in a new era for GN Otometrics; at the same time, Aurical #10,000 shipped from Taastrup

January, 2005
Following the acquisition of Fischer-Zoth by Natus Medical Inc., an agreement is signed with Natus for the distribution of AccuScreen

April, 2005
GN Otometrics launches 3 new products at AAA in Washington DC, the AURICAL Plus, MADSEN Conera and MADSEN Itera II

July, 2005
VG40 video goggles are introduced for VNG