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:
Jan. 04, 1983
Filed:
Feb. 12, 1981
Pierre Vachee, LaGaude, FR;
International Business Machines Corp., Armonk, NY (US);
Abstract
A time-division multiplexing method and device are disclosed for combining a data signal and several secondary binary signals into a train of pulses, whereby data signals can be transmitted at various bit rates in synchronous or asynchronous mode. The data signal and N secondary signals are multiplexed together using two different frames respectively termed 'synchronous frame' and 'asynchronous frame,' depending on whether data transmission is to be performed in synchronous or asynchronous mode. The asynchronous frame comprises a frame-alignment bit having a predetermined value, a data bit, and N bits pertaining respectively to the N secondary signals. The synchronous frame is divided up into n subframes, l.sub.1 bits in length each, where n is equal to the integer that is immediately larger than the quantity N/(l.sub.1 -2). Length l.sub.1 is defined by the relation l.sub.1 =LR/DR, where LR is the fixed bit rate for the pulse train resulting from the multiplexing process and DR is the bit rate for the data signal. Each subframe includes a synchronization bit whose value is complementary to that of the frame alignment bit, a data bit, and several bits pertaining respectively to the secondary signals. In addition, the last subframe includes a frame-alignment bit. Each bit within a synchronous or an asynchronous frame is associated with a control bit which has a first predetermined value when it is associated with a synchronization bit or a frame-alignment bit, and the complementary value when it is associated with a data bit or with a bit pertaining to the secondary signals. All of the frame bits together with the associated control bits are then encoded to be simultaneously transmitted over the transmission path. The frame bits define a data channel designated A, and the control bits define another channel designated B. The bits are paired off, with each pair comprising a channel A bit and the channel B bit associated therewith, and each of these pairs is encoded for transmission over the line. The invention also provides the demultiplexing method associated with the multiplexing method. The invention further provides an interface tansmitter and an interface receiver embodying the methods described above and allowing various DTE to exchange data, control and timing signals.