Browse Prior Art Database

ID Bit Scheme for Mulisynch Monitors

IP.com Disclosure Number: IPCOM000112173D
Original Publication Date: 1994-Apr-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 78K

Publishing Venue

IBM

Related People

Eagle, DJ: AUTHOR [+4]

Abstract

Disclosed is an extension of an existing ID bit scheme which does not require a change to the physical connection of display or adaptor. Old displays will work on new adaptors and new displays will work on old adaptors. A further level of information becomes available to new adaptors when new displays are attached.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

ID Bit Scheme for Mulisynch Monitors

      Disclosed is an extension of an existing ID bit scheme which
does not require a change to the physical connection of display or
adaptor.   Old displays will work on new adaptors and new displays
will work on old adaptors.   A further level of information becomes
available to new adaptors when new displays are attached.

Implementation adds little cost to new displays.  A hardwired
solution detects multisync capability rather than the user having to
input to a software select panel.

      For connection to both OEM and IBM video display subsystem it
is a requirement that the displays should conform to the industry
standard ID bit allocation for multisync displays, which is the IBM
8514 display ID.  It is desired when these displays are attached to
an IBM display adaptor, the availability of additional display
functions are indicated to the adaptor.  The current method employed
for display ID bits makes this impossible.  The IBM 8514 has ID
'1010'.  The most significant bit is shown first and thus ID bits 2
and 0 are grounded.  Bits 3 and 1 represent a high level - these are
pulled up in the adaptor.  The common method of implementing this is
not to populate these pins in the display plug.  The display adaptor
reads the ID bits and, depending on the ID read, sets the video
subsystem to drive the display in the appropriate modes using
predefined fonts.

      Some OEM 'multisync' displays are capable of operating over a
range of resolutions with the user having the ability to adjust the
displayed image to their individual requirements, needed because of
display resolutions each with a unique timing set.  IBM provides the
display with fixed modes which match IBM adaptors.  OEM displays
capable of using the highest IBM mode - XGA (implemented on the 8514)
ensured IBM compatibility by adopting the IBM 8514 display ID bits.
There has been improvement in the display resolutions available and
also in the function of OEM products but the 8514 ID has been
retained and is the industry stand...