Two Epson 1200S on one SCSI line?
Plamen Tanovski
I just can't get two Epson 1200S working on one SCSI line. Termination and IDs
are OK but I get a buss error when booting. Using one scanner with other SCSI
device works, but only when the scanner is the last device in the line with
termination.
Any suggestions?
best regards
CSM1
Are you sure you don't had a duplicate ID number?
Each device on a SCSI line must have unique ID numbers. SCSI IDs are 0
thru 7. One of those is reserved (7 I think).
A little Info.
http://www.pcguide.com/ref/hdd/if/scsi/confIDs-c.html
--
CSM1
http://www.carlmcmillan.com
--
isw
wrote:
Try booting with both scanners on the SCSI bus, but not powered. After
the boot process is done, turn them on. Or try booting with one powered
up, the other not.
Isaac
Bennett Price
terminator? Perhaps an active terminator is required.
Take a look at
http://www.pcguide.com/ref/hdd/if/scsi/cablesTermination-c.html
isw
Bennett Price <bjp...@cal.berkeley.edu> wrote:
> isw wrote:
> > In article <95chs6-...@tanovski.de>, Plamen Tanovski <p...@arcor.de>
> > wrote:
> >
> >> Hi,
> >>
> >> I just can't get two Epson 1200S working on one SCSI line. Termination and
> >> IDs
> >> are OK but I get a buss error when booting. Using one scanner with other
> >> SCSI
> >> device works, but only when the scanner is the last device in the line
> >> with
> >> termination.
> >>
> >> Any suggestions?
> >
> > Try booting with both scanners on the SCSI bus, but not powered. After
> > the boot process is done, turn them on. Or try booting with one powered
> > up, the other not.
> >
> > Isaac
> Perhaps cable length is too long?
Hard to imagine; SCSI is OK up to five or six meters. I've never seen
25-pin cables anywhere near that long.
> Are you using Epson's built in
> terminator? Perhaps an active terminator is required.
An active terminator offers reduced power consumption, but I don't see
why it would "terminate" better.
Just a thought: could it be that somehow the scanners' terminators are
*always* connected, regardless of what the switch says? That extra
termination will kill a SCSI chain right quick.
And another thought: ISTR that *some* devices using 25-pin SCSI
connectors did not provide terminator power. If you try something with
external ones (active or passive), that might be something to watch out
for...
Isaac
Plamen Tanovski
>> I just can't get two Epson 1200S working on one SCSI line. Termination
>> and IDs are OK but I get a buss error when booting. Using one scanner
>> with other SCSI device works, but only when the scanner is the last
>> device in the line with termination.
> Are you sure you don't had a duplicate ID number?
yes, the IDs are of course different.
best regards
Plamen Tanovski
>> Are you using Epson's built in
>> terminator? Perhaps an active terminator is required.
>
> An active terminator offers reduced power consumption, but I don't see
> why it would "terminate" better.
Epson explicitly advises not to use external terminator.
>
> Just a thought: could it be that somehow the scanners' terminators are
> *always* connected, regardless of what the switch says? That extra
> termination will kill a SCSI chain right quick.
This is also my suspicion and it explains why nothing works, if the scanner
is in the middle of the SCSI line.
best regards
isw
wrote:
> isw <i...@witzend.com> writes:
>
> >> Are you using Epson's built in
> >> terminator? Perhaps an active terminator is required.
> >
> > An active terminator offers reduced power consumption, but I don't see
> > why it would "terminate" better.
>
> Epson explicitly advises not to use external terminator.
That right there is a big clue that something odd is going on. I wonder
how Epson's implementation is in violation of the SCSI spec?
> > Just a thought: could it be that somehow the scanners' terminators are
> > *always* connected, regardless of what the switch says? That extra
> > termination will kill a SCSI chain right quick.
>
> This is also my suspicion and it explains why nothing works, if the scanner
> is in the middle of the SCSI line.
Actually, *if* the entire SCSI chain is fairly short, having one
"terminator" in the middle won't make any difference *as long as there's
not more than two total* -- SCSI rise and fall times are just not fast
enough for a foot or two of cable to produce a significant echo. More
than two terminators will alter the signal voltages sufficiently to make
level discrimination difficult.
Isaac
Bob AZ
Check each scanner individually to be sure the ID is not a problem.
Then make sure the addressing is compatable. With two identical
devices you do need to take the addressing into account. And there is
a possibility there will be addressing problems no matter what with
two identical devices on the same cables. Also the drivers for the
devices do need to be loaded before the OP boots. If you are not using
the scnners and have the computer booted it is sometimes possible to
reboot and make things work but not all the time. Sometimes I run two
Nikon 4500s with no problms but I do need to watch the booting.
Bob AZ