Robin G Wells

US Patent:

57395977, Apr 14, 1998

Filed:

Jun 10, 1996

Appl. No.:

8/661273

Inventors:

Warren D. Bailey - Pittsboro NC
Elie M. Najm - Raleigh NC
Robin C. Wells - Cary NC

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

H04L 1240

US Classification:

307 85

Abstract:

A communications adapter card includes a circuit arrangement for causing an electrical voltage to be supplied to the card from a first voltage source, even if a second voltage source is available, and from the second voltage source if the first voltage source is not available. The circuit arrangement includes a Field Effect Transistor (FET) with its gate electrode connected to a control circuit which puts the FET in an off-state to inhibit the second voltage source from supplying voltage to the card if the first voltage source is available, and puts the FET in an on-state to supply voltage to the card if the first voltage source is not available. The invention makes it possible for a single communications adapter card to be used to attache power managed and non-power managed personal computers (PCs) to a Local Area Network (LAN).