The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 03, 1984
Filed:
Dec. 29, 1981
Jerry J Heep, Arlington, TX (US);
Paul Schreiber, Fort Worth, TX (US);
Tandy Corporation, Fort Worth, TX (US);
Abstract
An interface circuit is disclosed for connecting a digital computer to a modem or other peripheral circuit through either a standard digital signal (RS232) 'port' or an audio-frequency 'port' normally used by the computer to store and retrieve information on audio-frequency magnetic tapes. The interface circuit allows the modem to be used economically with a small computer which does not have a standard RS232 'port'. In order to allow the modem to connect to the audio-frequency 'port' the interface circuitry combines filtered audio signals received by the modem from an associated telephone line with RS232 signals generated by the modem decoding circuitry to produce tone bursts which can be decoded by the computer audio-frequency port. The interface circuitry can accept either RS232 signals or tone bursts from the computer to be transmitted by the modem by automatically adjusting an internal threshold level.