At 11:40 AM 2/18/1999 David G wrote:
>
>. . . The original IBM PC provided only the 4" connector, and supported
>only transfers of 8 bits at a time.  The PC/AT added the second
>connector so it could transfer 16 bits at a time.  [Although the
>number of data lines was increased, there was no need to duplicate the
>various bus "control" lines.]
>. . .


Just to clarify, the additional connector of the
16-bit ISA BUS *does* provide additional control
lines, including the available secondary IRQs and
DMA lines which are not present in the 8-bit BUS.

Thus, some modems may have 16-bit edge connectors
to allow access to the IRQs of the secondary PIC,
such as IRQs 9, 10, and 11.

John Chin

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