Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of BE474226ApublicationCriticalpatent/BE474226A/fr
H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
H04L27/00—Modulated-carrier systems
H04L27/26—Systems using multi-frequency codes
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
H04L1/00—Arrangements for detecting or preventing errors in the information received
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
H04L1/00—Arrangements for detecting or preventing errors in the information received
H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals