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Browse Prior Art Database

Missing Pulse Detector for Remote Keyboard or Tablet Monitoring

IP.com Disclosure Number: IPCOM000116186D
Original Publication Date: 1995-Aug-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Glass, D: AUTHOR [+3]

Abstract

Disclosed is a a Missing Pulse Detector (MPD) which gives an indication of communication failure between remote infrared linked devices (such as between tablets, mice, or keyboards and their host), or between remote terminals and hosts in phone-line interfaces. In a preferred embodiment, the host or remote device broadcasts a periodic pulse. The MPD "listens" for this pulse. When the MPD detects a missing pulse, communication break-down is suggested and a light-emitting diode is lit or an audible tone is produced.

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This is the abbreviated version, containing approximately 55% of the total text.

Missing Pulse Detector for Remote Keyboard or Tablet Monitoring

      Disclosed is a a Missing Pulse Detector (MPD) which gives an
indication of communication failure between remote infrared linked
devices (such as between tablets, mice, or keyboards and their host),
or between remote terminals and hosts in phone-line interfaces.  In a
preferred embodiment, the host or remote device broadcasts a periodic
pulse.  The MPD "listens" for this pulse.  When the MPD detects a
missing pulse, communication break-down is suggested and a
light-emitting diode is lit or an audible tone is produced.

      The MPD circuit is mounted in the remote device (tablet,
joystick, keyboard, or terminal).  It may consist of a 555 timer
(8-pin mini Dual-In-line Package (DIP)) working in a monostable mode.
The circuit also contains a capacitor whose time delay is set to
slightly exceed time between incoming pulses.  The incoming pulses
continually reset the timing cycle.  A missing pulse allows the
timing cycle to finish and changes the output state.

      When a user of a remote keyboard with an Infrared Ray (IR) link
to host terminal is oriented in such a way that the terminal
communication breaks down, or perhaps there is an intervening object,
the MPD detects a missing pulse from the host, and flashes a light or
produces a tone to notify the user that communication has broken
down.  This embodiment is useful for blind people who may not be sure
that the remote keyboard is poi...