As early as 1937, telefax machines used by newspapers were using some kind of couplers, possibly acoustic but more likely magnetic for single-directional communication.
court ruling regarding the Hush-A-Phone in 1956 that the use of a phone attachment (by a third party vendor) was allowed for the first time; though AT&T's right to regulate any device connected to the telephone system was upheld by the courts, they were instructed to cease interference towards Hush-A-Phone users.
Multiplexed bidirectional telephone coupling was not needed by these early fax machines. Robert Weitbrecht created a workaround for the Bell restrictions in 1963.
Such modems or couplers were developed around 1966 by John van Geen at the Stanford Research Institute (now SRI International), that mimicked handset operations.
A second court decision in 1968 regarding the Carterfone further allowed any device not harmful to the system to be connected directly to the AT&T network.
An early commercial model was built by Livermore Data Systems in 1968.
The earliest major motion picture depicting an acoustic coupler was probably the 1968 Steve McQueen film Bullitt. == See also == Carterfone Federal Standard 1037C MIL-STD-188 Telecommunications device for the deaf == Notes == == External links == 1964 Livermore Data Systems Model A acoustic coupler modem surfs the web Digitronics acoustic coupler patent, January 5, 1971 Modems Network access Модем#История
The earliest major motion picture depicting an acoustic coupler was probably the 1968 Steve McQueen film Bullitt. == See also == Carterfone Federal Standard 1037C MIL-STD-188 Telecommunications device for the deaf == Notes == == External links == 1964 Livermore Data Systems Model A acoustic coupler modem surfs the web Digitronics acoustic coupler patent, January 5, 1971 Modems Network access Модем#История
With luck one could get 300 baud (~bits/second) transmission rates, but 150 baud was more typical. That speed was sufficient for typewriter-based terminals, as the IBM 2741, running at 134.5 baud, or a teleprinter, running at 110 baud. The practical upper limit for acoustic-coupled modems was 1200-baud, first made available in 1973 by Vadic and 1977 by AT&T.
In Australia, until 1975 the PMG, a Government monopoly, owned all telephone wiring and equipment in user premises and prohibited attachment of third party devices, and while most handsets were connected by 600 series connectors, these were rare in Australia so imported equipment could not be directly connected in any case, despite the general electrical compatibility. It was not until a landmark U.S.
With luck one could get 300 baud (~bits/second) transmission rates, but 150 baud was more typical. That speed was sufficient for typewriter-based terminals, as the IBM 2741, running at 134.5 baud, or a teleprinter, running at 110 baud. The practical upper limit for acoustic-coupled modems was 1200-baud, first made available in 1973 by Vadic and 1977 by AT&T.
1200 baud endpoints became widespread in 1985 with the advent of the Hayes Smartmodem 1200A, though it used an RJ11 jack and was not an acoustic coupler.
Acoustic couplers were still used until at least the late 1990s by people travelling in areas of the world where electrical connection to the telephone network is illegal or impractical.
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