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From: graifer@net1.UCSD.EDU (Dan Graifer)
Newsgroups: net.micro.mac
Subject: Re: mac modem cable
Message-ID: <258@net1.UCSD.EDU>
Date: Thu, 28-Aug-86 14:56:51 EDT
Article-I.D.: net1.258
Posted: Thu Aug 28 14:56:51 1986
Date-Received: Fri, 29-Aug-86 05:32:55 EDT
References: <1150@hou2h.UUCP> <1200@umd5>
Reply-To: graifer@net1.UUCP (Dan Graifer)
Organization: U.C. San Diego
Lines: 36


I was able to obtain MiniDIN-8 connectors from my Apple dealer (Computer 
Merchant of San Diego). I suspect they had them leftover from before they
gave up manufacturing cables themselves; The DIN-8 is B....!  I've heard of
others joining with a friend to buy an Apple ImagewriterII cable and cutting
it in half.  Anyways here is the cable I am succesfully using to connect my
Mac+ to a Hayes Smartmodem 1200:

Signal    DIN-8   Color   DB-25    Signal
HSKo        1     Orange    6       DSR
HSKi        2     Green     20      DTR
TxD-        3     Red       2       TXD
Gnd         4     Black     7       Sig. Gnd.
RxD-        5     Blue      3       RXD
TxD+        6
unused      7
RxD+        8
 (ShieldRing) (FoilShield)  1       Protective Gnd

The Apple Technote a friend showed me indicated that the first two should 
swapped.  It also indicated +12v for pin 1.  This didn't work, and also
makes no sense: handshake output is a signal from the modem to the Mac.  A
voltmeter told me the +v signal was on pin 2;  The smartmodem requires a +v
signal on DTR ready before it will operate. The above arrangement WORKS.
(you don't want to hook carrier detect (DB25 pin 8) to HSKo, as a Hayes  
compatable modem will accept control data when there is no carrier)

Some people have suggested that pin 8 (RxD+) should be tied to ground. I havent
done so, and have had no problem with the floating signal.  I have also heard
that grounding TxD+ can be physically damaging to the Mac.  I used 9 conductor
plus ground shielded cable: shielded cable is HIGHLY recommended.  If you can
get 5 conductor, you will have less trouble than I had getting the rubber 
jacket over the cable.

Good luck
Dan Graifer