Browse Prior Art Database

Cable Identification Extension

IP.com Disclosure Number: IPCOM000109042D
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 1 page(s) / 45K

Publishing Venue

IBM

Related People

Johnson, DWJ: AUTHOR

Abstract

In systems that are using multiple cables, multiple electrical interfaces are used. For any particular cable, one set of drivers and receivers is being used at any one time. Any other drivers and receivers are still connected to pins on the interface, but are not being used, so they do not connect to anything in the cable.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 84% of the total text.

Cable Identification Extension

      In systems that are using multiple cables, multiple electrical
interfaces are used.  For any particular cable, one set of drivers
and receivers is being used at any one time.  Any other drivers and
receivers are still connected to pins on the interface, but are not
being used, so they do not connect to anything in the cable.

      By connecting the cable ID pins to a driver in the cable
instead of shorting them to ground, the number of possible cable
types can be extended.  For example, suppose one cable type has an ID
of high-low, created by shorting the second line low.  On a new
cable, this second line could be connected to an active driver
instead of to ground.  If switching the driver makes the ID change,
then the cable can be differentiated from the first.  If there is
another surplus driver for that interface available, another cable
can be differentiated.

      Instead (or in addition to) the cable ID technique mentioned of
shorting pins to ground, or connecting the cable ID pins to a driver,
the surplus signals could be used to identify which cable is
attached.  By selectively connecting surplus drivers to surplus
receivers not normally being used on a particular class of
interfaces, a mechanism for identifying this cable is implemented.
The code can then determine through first testing for the base cable
ID, then selectively testing for connections possible with that ID to
determine which cable is attached....