SCSI terminators - active vs. passive

[twilyth]

I don't know if external SCSI devices even need manual termination - i would hope that by now it would automatic. But I have 2 external tape drives. One cannot successfully read or write a whole tape and I'm wondering if it could be a termination issue.

They are both 50-pin wide SCSI. The cable goes from the card to the TR5 drive (10/20gig) then another cable runs from the second port on drive #1 to a passive, pass-through terminator dongle and then into the second drive - a TR4 (4/8gig).

When the pass-through is at the end of the first cable, the TR4 works flawlessly. I'm going to try that configuration with the TR5 drive, but it would be nice to have a little understanding of what is going on.

 

[Sonido]

I don't know if external SCSI devices even need manual termination - i would hope that by now it would automatic. But I have 2 external tape drives. One cannot successfully read or write a whole tape and I'm wondering if it could be a termination issue.

They are both 50-pin wide SCSI. The cable goes from the card to the TR5 drive (10/20gig) then another cable runs from the second port on drive #1 to a passive, pass-through terminator dongle and then into the second drive - a TR4 (4/8gig).

When the pass-through is at the end of the first cable, the TR4 works flawlessly. I'm going to try that configuration with the TR5 drive, but it would be nice to have a little understanding of what is going on.

50 is narrow, 68 is wide. If you are using a 50-pin, I would imagine it's an Ultra2. External or internal, it will need a terminator. Since it's passive, it's possible it's stopping the signal from reaching the receiver at the needed strength. I don't remember what's the minimum voltage for the line, but it should be over 2.0v. Try an active one and see if it fixes the issue.

 

[twilyth]

I thought 25 pin was standard, SCSI Classic(Trademarked, all rights reserved)

 

[Sonido]

I thought 25 pin was standard, SCSI Classic(Trademarked, all rights reserved)

How dare you make me doubt myself! *Shakes Fist Angrily*

I'm pretty sure you are correct on the 25 classic, but 50-pin is called narrow. After 68-pin came to be, it was changed to narrow and 68 became known as wide. 2 50-pins is also known as Fast-Wide or Wide-Fast... something like that. I think that's what you have. If it is, then I was wrong and your original thought is correct. one 68-pin is also known as Fast-Wide or whatever that damn standard is called. I don't feel like looking crap up at this time of the morning.

 

[twilyth]

I don't feel like looking crap up at this time of the morning.

I feel ya'.