Acoustic coupler for high-speed modem

DETAILED DESCRIPTION The present invention is a novel and improved device for connecting a data modem to a telephone line by way of the acoustic handset.
The typical telephone set includes a handset containing a microphone and speaker mounted at opposite ends for use in voice communications by a person.
The typical data modem uses a single two-wire communication line that is readily adaptable for direct coupling to the telephone line via a conventional RJ-11 modular plug.
However, for the reasons discussed previously, direct access to the telephone line is often not available in hotels, at public pay phones, with cellular or portable phones, or with telephones found abroad that are installed to foreign specifications.
The data modem user is obliged to use indirect means to connect the data modem to the telephone line under these circumstances.
One method for such indirect connection involves the use of an acoustic coupling device which attaches to the acoustic telephone handset and converts the acoustic signal from the handset speaker into an electronic signal recognizable by the modem.
Such a coupler also converts a modem output signal into an acoustic signal which is broadcast into the telephone handset microphone for transmission into the phone line.
The present invention provides an acoustic coupling device for coupling a high-speed data modem to a standard telephone handset by overcoming the difficulties caused by inadequate signal-to-noise ratio (SNR) at the acoustic handset in high ambient acoustic noise environments such as those at public telephones in airports and on freeways.
The present invention further provides for indirect acoustic coupling of high-speed data modems to pay telephones, which use carbon microphones, and to non-standard phones such as are found abroad.
The present invention also provides a low SNR indirect coupling capability for standard data and telefax modems with no adjustment or improvement to the modem itself.
An illustrated embodiment of the present invention provides an acoustic coupler which can be held tightly against a standard telephone handset by means of a velcro strap and may be connected to a standard data modem by means of a length of wire terminated in the standard RJ-11 modular plug