This guide is intended to answer some common questions about termination without being overly technical. It gives you a basic idea of when to use certain terminators without all the technical jargon.
Do I need a Terminator?
All SCSI buses must be terminated at each end. If you are simply connecting an external device to a SCSI card then your bus is already likely to be terminated and you just need to buy the external cable. If you are installing a new SCSI bus then you will need to terminate it.
How do I terminate my devices?
On an internal ribbon cable the last connector must be plugged in to a terminated device or have a terminator plugged in to it. External termination may be necessary if you have unused external SCSI ports connected to your SCSI bus.
What is the difference between an Active and a Passive Terminator?
An Active terminator has a small voltage regulator which terminates the devices at the correct voltage. Active Terminators are required for Devices running at ultra SCSI Speeds. If in doubt you should go for an Active Terminator.
My last device is not terminated, and I cannot place a terminator on the cable, what do I need to do?
You will need a pass through terminator; this is simply a terminator with two connections, one to plug the cable in to and one to plug in to a device.
I've found the terminator I need but it's pass-through and I only need to connect one end, does this matter?
No, Pass-Through Terminators do not need to be connected both ends to function correctly.
Iíve seen an adapter with upper byte termination, what is this?
If you are connecting a narrow device (50 pin) on a wide SCSI bus (68 pin) that is already attached to some wide SCSI peripherals you will require an adapter with upper byte termination.