Browse Prior Art Database

Full Duplex Operation

IP.com Disclosure Number: IPCOM000082671D
Original Publication Date: 1975-Jan-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 3 page(s) / 43K

Publishing Venue

IBM

Related People

Frisone, JB: AUTHOR

Abstract

Described is an improvement in the full-duplex operation of the loop disclosed in U.S. Patent 3,752,932. The improvement is illustrated in the drawing and includes only those circuits necessary to perform the functions required to implement the improvement. Reference may be made to the above patent for any additional information.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 3

Full Duplex Operation

Described is an improvement in the full-duplex operation of the loop disclosed in U.S. Patent 3,752,932. The improvement is illustrated in the drawing and includes only those circuits necessary to perform the functions required to implement the improvement. Reference may be made to the above patent for any additional information.

In the full-duplex operation described in the patent, a central station may transmit data to a station upstream from a transmitting station. When the address of the intended receiving station is received, this station goes into the receive mode in which it receives data from the central and transmits 1's downstream. The stream of 1's is, of necessity, interrupted while the address is being transmitted. If this should occur while the downstream transmitting terminal is still transmitting data, the unique code between messages described in the patent is unaffected. However, should this occur or overlap the termination of transmission, the unique code will not occur between messages from different terminals. This may be overcome by having each terminal transmit a unique ending pattern, however, the subsequent 1's transmitted by the central or an upstream terminal will form another unique code, thus decreasing information throughput.

The solution described eliminates this double-code situation and materially improves information throughput or line capacity utilization, especially so in those instances where short messages are transmitted. This is accomplished at the transmitting terminal by transmitting an ending 0 bit at the end of a message, and thereafter monitoring the next six incoming data bits.

As soon as one of the next six following bits is a 0, the terminal completes by transmitting an intermessage code. For examp...