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From: david@cs.uow.edu.au (David E A Wilson)
Newsgroups: sci.electronics
Subject: Re: Looking for DD-50P SCSI terminators
Keywords: standards? what standards :-)
Message-ID: <1990Aug22.045225.23292@cs.uow.edu.au>
Date: 22 Aug 90 04:52:25 GMT
References: <8287@ncar.ucar.edu>
Organization: Dept of Computer Science, Wollongong University
Lines: 26

cook@stout.atd.ucar.edu (Forrest Cook) writes:
>While on the topic of SCSI,  is the SCSI standard only for signal lines,
>not connectors?  So far, we have the following SCSI connectors:

>DD-50				Sun 4/280 and some peripherals
>mini DD-50			Sun Sparcstations
>dual-inline 			Most circuit board SCSI connections
>AMP "centronix"			who knows?
>AMP MT shielded dual-inline	Ardent, Emulex
>DB-50				Macintosh
    25

The standard specifies the dual-inline form for the circuit board.
The appendix to the standard (NOT part of the standard) has the 50 way
AMP connector (like the Centronics 36 way connector only wider) as alternative
2. I cannot remember what alternative 1 was.

The Sun DD-50, Sun sub micro SCSI & Apple DB-25 connectors are not mentioned
but then the standard does not mandate specific external connectors.
 
>I also just received an STC 9 track tape drive that has an option for
>"differential" SCSI,  that shoots down the idea of an electrical standard.
That is part of the standard as well. By using differential signals you can
have longer cable runs etc. Pity the connectors are the same.

David Wilson	Dept Comp Sci, Uni of Wollongong	david@cs.uow.edu.au