Date   : Mon, 12 Jan 2004 20:48:47 GMT
From   : Pete Turnbull <pete@...>
Subject: Re: Host adapter Issue D

On Jan 12, 13:01, Mark Usher wrote:

> And as if by magic the hard drive appeared. Thanks for that. Now to
do
> some tests to see if this board will work well straight through to
SCSI
> drives. I think also I *must* hook up 2 host adapters to one system
for
> the fun of it.
>
> To put both on the 1MHZ bus must I simply put them on the same 34
ribbon
> cable?
>
> <BBC>-------->Host 1<------->Host 2<
>
> Or is some sort of termination recquired?

Well, yes, you do daisy-chain them, and in theory there should be
termination at the end of the bus.  The host adapters usually have a
set of resistor packs labelled RP2...RP4.  They're socketed, and you
should remove them from all but the last unit on the bus.  If your
adapters came from stacking units, the packs may not be there (Stacking
Filestores came with a terminator plug instead).  You can add them
easily enough.  RP2 and RP3 are 16-pin DIL 2K2 resistor packs, each
containing 15 resistors, with as common connection to pin 16.  RP4 is a
16-pin DIL 2K2 resistor pack containing 8 individual resistors.  Both
types are readiliy available from Farnell etc.

Another resistor pack, labelled RP1, is a 220R/330R terminator pack for
the SCSI bus; leave that in on each unit.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York