Brian Christopher Longwell

US Patent:

47165618, Dec 29, 1987

Filed:

Aug 26, 1985

Appl. No.:

6/769509

Inventors:

Eric H. Angell - North Andover MA
Thomas J. Aprille - Andover MA
Juan O. Azaret - North Andover MA
Rong-Chin Fang - North Andover MA
Byeong G. Lee - Methuen MA
Brian C. Longwell - Kingston NH
Craig A. Sharper - Bradford MA
Jan-Dieter Spalink - Woodbridge VA

Assignee:

American Telephone and Telegraph Company, AT&T Bell Laboratories - Murray Hill NJ

International Classification:

H04J 110
H04J 308

US Classification:

370 55

Abstract:

In a transmission system, adding and/or dropping any one or more of a plurality of digital signals of one or more digital transmission bit rates is facilitated by employing a unique transmission signal in which data words associated with individual digital signals are arranged in prescribed groups. The transmission signal data word groups are obtained by formatting the individual digital signals to be combined into a unique channel frame format common to all of the digital signals and by employing a unique one-step multiplexing process to insert digital words from the channel frames into the group of data word positions in the transmission signal associated with the particular signal being combined. Consequently, digital signals may be added to the transmission signal by formatting them into the common channel frame format and, then, inserting the digital words therefrom in the one-step multiplexing process into an associated group of data words positions in the transmission signal. Digital signals are dropped from the transmission signal by extracting associated groups of data words from the transmission signal, identifying the corresponding channel frames and deformatting the data bits from channel frames of corresponding digital signals being reconstructed.