Carousel Volume 2 #1/carousel.iso/mactosh/tech/macintos.rs2

Internet Message Format | 1986-03-12 | 9.1 KB

Date: Sat 18 Feb 84 17:35:33-MST
From: Randy Frank <[e-mail]>
Subject: pin outs for the rs232/422 connectors
To: [e-mail]

Here are the pinouts for the RS232/422 connectors

1 - Ground
2 - +5  (may turn into an output handshake, don't use)
3 - Ground
4 - Transmit data +
5 - Transmit data -
6 - +12 (for detecting power on ONLY)
7 - Clear to Send (CTS) or Transmit Clock (TRxC) depending on mode
8 - Receive data +
9 - Receive data -

For RS232 levels, use the Xmit and Receive - (minus) pins and ground.

DON'T ATTEMPT TO DRAW POWER FROM THE +5 OR +12 LEADS.  THE SHOULD ONLY BE USED
TO SENSE IF THE MAC IS POWERED UP.

I finally got an Imagewriter w/o a cable, and built one according to these
specs and it works very nicely.  Data Terminal Ready (DTR) from the
Imagewriter goes to pin 7 (CTS), and the Imagewriter should (obviously) be set
for DTR flow control and not xon/xoff.

This is everything I now know about these interfaces; plz don't send me msgs
asking for any more info (such as questions about the pin 7 mode) since I
don't know anything else!  I also have no idea what is meant by the comment
on pin 2.  I am copying from a sheet of paper given to me, and you now know
what I know...

For those who don't understand why there are two transmit and receive pins,
they are for the rs422 mode, which use a balanced pair for transmit and
receive instead of a ground-relative signal. As mentioned about, ignore the
+ pins for rs232 levels.

Randy
-------
Date: Tue 10 Apr 84 17:02:53-EST
From: Paul R. Johnson <[e-mail]>
Subject: Imagwriter Cable
To: [e-mail]

Having perused the MACINTOSH.RS232 document in <INFO-MAC> at
SUMEX I came up with the following four wire answer to my
question about the pin-to-pin connections between a Macintosh
and an Imagewriter:

Macintosh  Imagewriter

  3 ---------- 7
  5 ---------- 3
  7 ---------- 20
  9 ---------- 2

Seems to work fine with both MacPaint and MacWrite, but we've
only used it an hour or so.  I'll let you know if any problems
develop.

---Paul Johnson
-------
15-May-84 15:43:08-PDT,1306;000000000000
Mail-From: PATTERMANN created at 15-May-84 15:40:46
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Received: from SU-SCORE.ARPA by SUMEX-AIM.ARPA with TCP; Mon 14 May 84 22:25:43-PDT
Date: Mon 14 May 84 22:18:34-PDT
From: Joseph I. Pallas <[e-mail]>
Subject: Re: Query on rs232/422 mac connectors
To: [e-mail]
cc: [e-mail]
In-Reply-To: Message from "Dave Farber <[e-mail]>" of Mon 14 May 84 17:39:58-PDT
ReSent-date: Tue 15 May 84 15:40:42-PDT
ReSent-From: Ed Pattermann <[e-mail]>
ReSent-To: info-mac: ;

    We are getting about 2.5 volts out of our mac on pin 7. Is that
    normal? I believe the specs for rs232 say > 3 volts

It can't be considered abnormal, since (according to the pinout in
<info-mac>macintosh.rs232) pin 7 is an input.  The Mac represents
an rs232 Data Terminal, not Data Set.  If you're talking to a modem,
pin 7 should go to rs232 pin 5.  The connections I used are:

    Mac        Modem
    3        7
    5        2
    7        5
    9        3

Some modems will want to see DTR (pin 20) active also, which can be
faked by tying it to pin 5 (I'm not sure if that's the canonical way
to fake it, though).  Other modems will ignore DTR or can be made to
(e.g., USR Password has a switchable option).

Hope that helps!

joe
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24-May-84 10:19:36-PDT,797;000000000001
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Date: 24 May 84 13:18:43 EDT
From: Lawrence <[e-mail]>
Subject: Re: Query on rs232/422 mac connectors
To: [e-mail]
cc: [e-mail]
In-Reply-To: Message from "Dave Farber <[e-mail]>" of 14 May 84 13:27:29 EDT

Pin 7 on an rs232 connector is signal ground.  This is the reference for
measuring other voltages on the connector.  The other signals of interest
appear on pins  2,3,4,5,6,8, and 20.  The voltage levels should be greater
than 3 volts and less than 15 volts for a space, and less than minus three
volts and greater than minus 15 volts for a mark.
Ref: RVK

Lawrence Fischer
Lfischer@Rutgers
-------

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From: Barry Leiner <[e-mail]>
Date: 3 Mar 1986 1416-PST (Monday)
Subject: 2 cables that work with MAC +

After a great deal of aggravation of dealing with dealers and trying to
get correct information (as opposed to information), I made the
following cables and they work. Caveat emptor

1. cable to connect MAC + to imagewriter I

DIN8    DB25    signal name

2    20    DTR/HSK
3    3    Xmit
4    7    signal ground
5    2    Rcv
8-jumpered to 4 on DIN8

2. cable to connect MAC + to modem (Prometheus)

DIN8    DB25    signal name

1    5    CTS
3    2    Xmit
4    7    signal ground
5    3    RCV
8-jumpered to 4 on DIN8

------------------------------

Comments:

a. I chose to actually jumper the DIN8 connector.  Hard to do, but not
impossible.

b. Much of the confusion comes from the fact that the MAC+ signal names
are those of a DTE (so far, so good) but the printer is also a DTE.
HOwever a modem is normally a DCE. Hence the cables have to be
different.

c. The pins used on the DB25 connectors are those used on the original
cables that came with my MAC (not +).

d. Note that this cable requires only 4-wire connector (which was all I
had laying around).

Barry Leiner

------------------------------

Date: Fri, 28 Feb 86 19:38:27 est
From: [e-mail] (Richard Kalagher)
Subject: poor man's mini 8 cable

I am sending this message on a Mac-plus using the mini-8 modem port without
a connector.  If you are careful, you can strip about a quater inch off
of the end of a wire and stuff it into the connector holes on the Mac
Plus.  I am using some fairly stiff four conductor cable from Radio Shack.
The following connections seem to be working for my modem (a Ven-Tel):

Mac Plus DIN-8                   Stnd RS-232 Connector

      1                                 20
      3                                 2
      4                                 7
      5                                 3

The Mac Plus DIN-8 looks as followers:

    8  7  6
  5   4  3
     2  1
This is of course not good engineering practice and I take no responsibility
if you Zap something.  But if you are careful and can't wait however long
it will take to get a real cable, this might substitute.  Good luck.

------------------------------


Date: Sun, 23 Feb 1986 17:29 EST
From: Dave Elbon  <[e-mail]>
Subject: Mac+ Serial Cables

I've located the Mac Technical Note (#65) with the Mac+ pinouts.  The
serial ports look like this:

Macintosh Plus Serial Connectors

Mini DIN-8

(Female Connector)

      *  *  *
      8  7  6
     *   *  *
     5   4  3
        *  *
        2  1

Pin  Name           Description/Notes
---  ----           -----------------
 1   HSKo           Output Handshake (from Zilog 8503 DTR)
 2   HSKi/Ext. Clk  Input Handshake (CTS) or TRxC (depends on 8530 mode)
 3   TxD-           Transmit Data
 4   Ground
 5   RxD-           Receive Data
 6   TxD+           Transmit Data
 7   Not Connected
 8   RxD+           Receive Data (ground this line to emulate RS-232)

I've not had a chance to use this yet.  What I need is some Mac+ to
regular 25-pin RS-232 cables.  My dealer didn't have anything like
that and I don't know where to get the mini-8 connectors in town, so
I bought a mini-8-to-mini-8 cable (called a Mac+ peripheral cable, I
think), and cut it in half.  Now I just need to add the 25-pin
connectors and I should be ready to go.  The cable is not a straight-
through, I believe several lines are crossed so the color coding
probably won't be the same on the two ends.  Remember, I haven't
actually done this yet, but it sounds good.
Acknowledge-To: Dave Elbon <SYSDAVE@UKCC>

------------------------------


From: HALL (5856)
Subject: Mini 8 Connectors
Date: 13-FEB 20:38 Hardware & Peripherals

[ This is in regard to the notice about Mac+ connectors from Jameco in the
previous Delphi Digest - Jeff ]

No, unfortunately, my sources (a dealer and others) weren't quite
right. The DIN 8 is not what is used on the Mac+.  They are called
"Mini 8s", and although they look similar to the DIN 8s, aren't the
same.  Apparently, the Mini 8s are smaller, and the pin arrangement is
slightly different.  The place to get the Mini 8s is H & B Associates
in California.  Their phone number (outside of California) is
1-800-423-3014.  I don't know what their California number is, but you
can call Harmonix at [phone], and ask for Mike Ferrera.  He can
give you their other number(s).  The connectors are $3.90 each in
quantities under 25.

Sorry about the confusion.

Brian Hall

------------------------------

From: RICFORD (5881)
Subject: Mac Plus 8-pin adaptor cables
Date: 14-FEB 15:53 Hardware & Peripherals

Thanks to ADVISE and some leg-work, I think I've stumbled on a good supplier of
Apple cables, specifically 8-pin -> 9-pin adaptor cables.  They've got them in
stock and claim to be supplying them to Cupertino...

C Enterprises 310-110 Via Vera Cruz San Marcos, CA, 92069 619-744-8182

Ric Ford

"MacInTouch" newsletter

P.S.  They're hand-soldered, guaranteed for life, and cost $10-13 depending on
quantity.

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