CompuServe Messages

No, you always want to have terminators on each _end_ of the bus. Always two terminators…..no more, no less. (Well, 99.99% of the time….) An active terminator replaces _one_ of the two terminators. In the case you sight, it should be: COMPUTER (terminated) ->Dev1->Dev2->Dev3 (terminated) In the case of a board with both an internal connector and an external connector, it should be: Dev1 (terminated) ->COMPUTER (not terminated)->Dev2->Dev3 (terminated) BTW, AFAIK, the best way to 'visualize' a terminator is to consider what it's purpose is: to dampen signal reflections in a line. I'm not really an 'analog' guy, but I've been told that the main reason to have a terminator is to eliminate signal reflections in an electrical line. Consider the attenuation you can see on an NTSC signal – where square waves turn into rounded hills, and improper termination can lead to ghosting. Supposedly, when dealing with high-speed digital signals like a SCSI bus, the same problems can crop up. Everytime there is a junction (connector), a small difference in impedance can result in a reflected signal. Because SCSI data uses high frequency digital pulses on each data line, they tend to act like complex RC circuits, where the actual SCSI cable takes on capacitor-like properties. All the high speed digital data ends up turning into mush by the time it reaches certain devices. An active terminator acts to dynamically minimize the high-speed transients on each line, resulting in a reduction of noise, and squarer pulses. (Don't ask me how….) PPS: double speeds are 'antiquated'. For $20 more than the SONY you found, you could get a quad-speed. (Less for internal 4x speed drives…) The saga continues…. Erik Flom