Browse Prior Art Database

Elastic Loop Interface

IP.com Disclosure Number: IPCOM000073586D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Lem, DJ: AUTHOR

Abstract

This is a method and apparatus for the insertion or extraction of various size data slots from a data communication loop or multidrop line.

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Elastic Loop Interface

This is a method and apparatus for the insertion or extraction of various size data slots from a data communication loop or multidrop line.

An external message is inserted into the loop following the end of any message mn which is circulating in the loop without writing over any of the information in the subsequent message mn + 1. Line 10 is a portion of a loop structure through which messages continue to circulate and was to be made available to units on the line, not shown. Across line 10, is a shift register or delay unit 12 which may be employed by the opening of switch S1. Contained within delay unit 12, is a message mb or data slot which is desired to be placed after the end of some data slot being communicated on the line 10.

The structure shown forms some portion of a terminal that is attached to the line 10. Data slots are monitored by some device in the terminal subsystem, not shown. Upon detecting the marker M which indicates the end of message, switch S1 is open. Then the subsequent message mb will enter delay unit 12 one bit at a time by selectively activating gates 14 and 16. As bits from the line 10 are entered into the delay unit 12, the external message mb is sequentially introduced onto line 10. The switch Sl will remain open following the insertion of mb, thus effectively increasing the total delay existing in the loop.

When it is desired to extract a data slot that is circulating in the loop, the switch S1 is closed at t...