US 4,236,248 AGranted

Transmission speed switching system

OwnerHiroichi Teramura, Yasuhiro Yamazaki +1inventors

InventorsHiroichi Teramura, Yasuhiro Yamazaki, Yasushi Wakahara

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Abstract

A transmission speed switching system for a transmission system having at each party of said transmission system a plurality of data MODEMs of different transmission speeds b.sub.1, b.sub.2, . . . b.sub.n, in which a carrier is modulated by a code train at intervals of a time S equal to a common multiple of symbol intervals S.sub.1, S.sub.2, . . . S.sub.n respectively corresponding to the transmission speeds in a manner to obtain a predetermined modulated wave which instructs said MODEMs of the other party the switching to a specified one of the transmission speeds, and in which the modulated wave is transmitted to the receiving station so that a demodulated code by a demodulator of any of the transmission speeds may be interpreted as the code train indicating the specified transmission speed to be selected by the receiving station, thereby switching the transmission speed to the specified one corresponding to the result of the interpretation.

Claims3

Dependent claims

A transmission speed switching system comprising:

a plurality of first multi-phase modulation data MODEMs of different transmission speeds b.sub.1, b.sub.2, . . . b.sub.n each operating in a multi-phase modulation mode and connected to a transmission line at one party of a communication system formed through said transmission line, one of said first data MODEMs being activated in correspondence to an instant one of the transmission speeds;
a plurality of second multi-phase modulation data MODEMs of said transmission speeds b.sub.1, b.sub.2, . . . b.sub.n each operating in a multi-phase modulation mode and connected to said transmission line at the other party of said communication system, only one of said second data MODEMs being activated in correspondence to an instant one of the transmission speeds;
modulation means connected to said first data MODEMs to modulate a carrier by a code train at intervals of a time S equal to a common multiple of symbol intervals S.sub.1, S.sub.2, . . . S.sub.n respectively corresponding to the transmission speeds in a manner to obtain a predetermined modulated wave which instructs the activated one of said second MODEMs for switching to a specified one of the transmission speeds;
demodulation means connected to the activated one of said second data MODEMs to demodulate said predetermined modulated wave through said activated one of said second data MODEMs to provide said code train;
and
control means connected to said demodulation means and said second MODEMs to activate only one of said second MODEMs indicated by said code train.

3 more elements

Dependencies are inferred from the claim text.