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Author Topic: Cable adapters for CS MKIII scsi  (Read 2248 times)

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Offline stopthegop

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Re: Cable adapters for CS MKIII scsi
« on: December 05, 2006, 05:14:09 PM »
[qoute]Doesn't the controller terminate one end? Also would the terminator on the cable I linked do the job?
[/quote]

No.  BOTH ends need to have active "single-ended(SE)" LVD(Low Voltage Differential) terminators.  Disable termination on all devices including the controller, and terminate at the cable ends with above mentioned terminators.  That means you need a FOUR position cable to hook up one scsi hard drive, a FIVE position cable to hook up two hard drives, a SIX position cable to hook up three drives, and so on.  You need one position for the cyberstorm, two positions for a terminator at each end, and one position for the hard drive.  Add one, obviously, for each additional drive.  Make sure NEVER to hook up a "Differential" aka "HVD(High Voltage Differential) SCSI device to a cyberstorm, or any other LVD bus for that matter.  HVD uses a +5v high, LVD uses 3.3v.  Obviously icompatible, the former can destroy the latter if improperly connected on the same bus with power applied.    
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Offline stopthegop

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Re: Cable adapters for CS MKIII scsi
« Reply #1 on: December 05, 2006, 06:16:23 PM »
Maybe I'm a little paranoid for using excessive packing materials... ?  I did work at UPS as a teenager for one summer.  I've witnessed -- even participated in -- the abuse of parcel packages.  It ain't pretty.  :)  

To clarify the scsi question, passive HVD terminators won't hurt anything on an LVD bus.  It just won't work.  An HVD device on the other hand, will do damage to an LVD controller and to other LVD devices that happen to be connected when power is turned on.  

The easiest way to tell the different types of SCSI is by looking at the scsi "diamond" symbol of the device in question.  A basic four sided diamond is SE "Single Ended".  If the diamond has a "carrot" (like this: "< <|>") on the outside to the left, its HVD or "Differential SCSI".  Never use such devices on a cyberstorm.  Fortunately, these are not as common.  If it has a "carrot"  on the inside of the diamond then it is what is called "LVD/SE".  This is the newest and the fastest protocol.  It is also the most tempermental.  Very sensitive to cable length, proper termination, parity errors, impedence mismatches (bent pins, etc), cable quality, etc.  These devices are great for using with the cyberstorm.  Just use the highest quality cables and keep the total lenght of the circuit as short as possible.  Max is 3M.  Thats the spec.  "Real world" Max is about 1M for best performance.  Buena Suerte Amigo!..    :-D
Primary:
A4000T. Phase5 PPC604e-233mhz/060-66mhz. Mediator, Z3 Fastlane, Voodoo5, Delfina, X-Surf, AD516, Peggy Plus.

Collection:
A4000D, A1200, A500, Milan060 (Atari clone), Atari MegaSTE, Atari TT030, C64, C128, Mattel Aquarius, (2) HP Jornada....