|01-25-2007, 07:46 AM||#1|
Join Date: Aug 2006
I'm a little confused about SCSI termination. I see terminators that are called active. Are there inactive terminators? Could someone explain a little about this to me and their use? Thanks, Dan :-?
|01-25-2007, 07:49 AM||#2|
Defender of the Faith
Join Date: Jan 2007
Re: SCSI Termination?
taken from http://www.ramelectronics.net/html/scsi_terminators.html
Passive SCSI Terminator: Uses resistors for temination. Use for SCSI-1 or slow SCSI-2
Active SCSI Terminator: Regulated termination. Used for Fast SCSI devices.
Active Negation: active SCSI terminator with enhanced circuitry for cleaner signal. Best to use with the Ultra SCSI's
Feed-through SCSI terminator: Use this if you have no more connectors left on your cable to connect a SCSI terminator. You plug the last connector in one side of the SCSI terminator and then plug the other side of the terminator into your last device. Helps keep cable lengths short.
When a wide SCSI bus or device must connect to a narrow SCSI bus or device, care should be taken to assure the proper termination of the high data byte. What's the high data byte? Well, "wide scsi" means 16 bit or 2 "bytes" (8 bits make a byte) scsi. Narrow scsi is 1 byte (8 bits) scsi. Normally wide scsi devices will work just fine using only the first byte, and therefore can be used on a narrow bus (cable). The problem is that if the second or "high byte" just, sort of, disappears, then it will not be terminated properly and all sorts of problems can occur. Also, whereas the wide drives of the past (non LVD) were perfectly happy to be directly connected to a narrow bus with no termination at the drive itself, it seems that most LVD (Ultra2 or Ultra160) drives require this high byte to be terminated at the drive.
LVD/SE SCSI Terminator: You can use this type of SCSI terminator with either Ultra2 LVD SCSI, Ultra160 SCSI or Ultra Wide SCSI. Any of these specifically called "LVD/SE" are multi-mode terminators and will automatically sense the bus "mode". A good way to ensure future compatibility for Ultra Wide users.
To err is human ... to BOING divine!
|01-25-2007, 07:59 AM||#3|
Kindred of Babble-on
Join Date: Sep 2004
Location: Ioannina , Greece
Re: SCSI Termination?
LVD/SE terminators did not work for my on my csppc scsi setup. I use normal "active" ones.
just a note...
|scsi , termination|
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