🚀 go-pugleaf

Tom Bird wrote, about SCSI terminators (edited beyond recognition):

> What's differential, active, passive and so on?

A differential terminator is for differential SCSI.
 
Passive termination is with resistors, active with semiconductor 
components.

From my files:

Usually terminating resistors will suffice over short distances, like 
2-3 feet, but for longer distances active termination is a real 
advantage.

Active termination provide the following advantages:
- Helps reduce noise.
- A logic bit can be used to effectively disconnect the termination.
- Regulated termination voltage.
- SCSI-2 spec. recommends active termination on both ends of the scsi bus.
- Improved resistance tolerances (from 1% to about 3%)
- Reduces current drawn from TERMPWR line.

To tell if an unmarked terminator is active, measure the resistance 
from the TERMPWR pin to an adjacent GROUND pin. Reverse the probes 
and take another reading.

If the reading is about 30.5 Ohms, with the probes both ways, you have a
passive single-ended terminator.

If the reading is about 45 Ohms, with the probes both ways, you have 
a passive differential terminator.

Active terminators should read much higher and give very different 
readings with the probes interchanged.

HTH,
-- 
Michael Salem