I realize that a SCSI terminator is normally required. Is there any
reasonable explanation why the scanner would perform flawlessly
without a terminator, but not run reliably WITH a terminator?
Alan
> In <[log in to unmask]>, on 03/02/00
> at 09:50 PM, Alan Eugene Davis <[log in to unmask]> said:
>
> >I connected a Microtek X6EL to the SCSI2 channel of an Adaptec
> >2940U2W. The scanner is currently the only device on that card,
> >and is connected through the DB25 to DB25 cable supplied with the
> >scanner, through a converter/bracket from a 50pin internal cable.
>
> >I installed this scanner before I saw the terminator in the box,
> >without the terminator. After recompiling the kernel to
> >recognize SCSI generic devices, I installed relevant packages on
> >my Debian GNU/Linux system, the SANE-related packages.
>
> >After running
>
> > $ scanimage --list-devices
>
> >the scanner was identified, and, ever since, there has never been
> >a need to fiddle---whenever I start the software, either through
> >The GIMP or via xscanimage itself, the scanner works flawlessly.
>
> >After I discovered the DB25 SCSI terminator in the packing, I
> >installed it. Not only will the scanner not work correctly with
> >it installed; but the terminator is quite warm to the touch.
> >Since I removed the terminator, the scanner has been performing
> >flawlessly.
>
> >Can someone explain the seeming anomalous behavior regarding the
> >terminator? I can only think that the Adaptek 2940U2W doesn't
> >need a terminator, while perhaps the Adaptec 2902E/I does need
> >it.
>
> >What gives?
>
> >Alan Davis
>
>
>
> >--
> >[log in to unmask]
>
> Alan:
> The SCSI bus requires proper termination to operate correctly. The
> normal configuration is to terminate each end of the bus. Some
> devices have terminators built in, while others require external
> terminators. The same is true of the cards, although most have
> terminators on board. The terminators dissipate considerable
> power, so warm is ok.
>
> As a note, some SCSI cards allow both internal and external
> devices. In this case, the boards termination should be disabled,
> and the ends of both device chains terminated.
>
>
> jan lambert
>
--
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