[comp.sys.mac.misc] Wiring for hayes modem w/handshaking

aciemian@ics.uci.edu (Alan Ciemian) (03/23/91)

A few people have requested that I post the cable wiring for a 
mac DIN-8 to modem w/handshaking.  Thanks and apologies to 
Software Ventures.

MAC DIN-8        modem 25 pin
----------------------------------
pin 1      to    pin 4 and pin 20
pin 2      to    pin 5
pin 3      to    pin 2
pin 4      to    pin 7
pin 5      to    pin 3

There is also a jumper from pin 4 to pin 8 on the mac side (or also
connect mac pin 8 to modem pin 7.


To adapt a standard cable at the modem end wire an adapter as follows:


mac side    modem side
-----------------------
pin 2      to pin 2
pin 3      to pin 3
pin 5      to pin 5
pin 7      to pin 7
pin 20     to pin 20
pin 20     to pin 4


PLEASE, no flames if you don't agree with this. I'm just passing on the

sethcohn@alchemy.tcnet.ithaca.ny.us (seth cohn) (03/24/91)

aciemian@ics.uci.edu (Alan Ciemian) writes:

> A few people have requested that I post the cable wiring for a 
> mac DIN-8 to modem w/handshaking.  Thanks and apologies to 
> Software Ventures.
> 
> MAC DIN-8        modem 25 pin
> ----------------------------------
> pin 1      to    pin 4 and pin 20
> pin 2      to    pin 5
> pin 3      to    pin 2
> pin 4      to    pin 7
> pin 5      to    pin 3
> 
> There is also a jumper from pin 4 to pin 8 on the mac side (or also
> connect mac pin 8 to modem pin 7.
> 
> 
> To adapt a standard cable at the modem end wire an adapter as follows:
> 
> 
> mac side    modem side
> -----------------------
> pin 2      to pin 2
> pin 3      to pin 3
> pin 5      to pin 5
> pin 7      to pin 7
> pin 20     to pin 20
> pin 20     to pin 4
> 
> 
> PLEASE, no flames if you don't agree with this. I'm just passing on the

not to press a point BUT that cable will not do carrier detect at all
since no pin is left to use with DCD (carrier detect - pin 8 of db25)

I think it's ridiculous that the mac won't do Handshaking AND carrier 
detect at the same time.  Gimme a good db25 for the mac.
Seth

Seth Cohn, Service Tech.  607-273-2815 voice 607-272-7002 BBS
All things posted are opinions by me, of me, for me, or to me.
And another thing..........I'm not sure you're real.

ogawa@orion.arc.nasa.gov (Arthur Ogawa) (03/24/91)

In article <27EB1B0B.3468@ics.uci.edu> aciemian@ics.uci.edu (Alan Ciemian) writes:
|A few people have requested that I post the cable wiring for a 
|mac DIN-8 to modem w/handshaking.  Thanks and apologies to 
|Software Ventures.
|
|MAC DIN-8        modem 25 pin
|----------------------------------
|pin 1      to    pin 4 and pin 20
|pin 2      to    pin 5
|pin 3      to    pin 2
|pin 4      to    pin 7
|pin 5      to    pin 3
|
|There is also a jumper from pin 4 to pin 8 on the mac side (or also
|connect mac pin 8 to modem pin 7.

For your reference, the above pinout is _not_ the same as that provided
with the Prometheus ProModem I recently purchased. The latter does _not_
jumper modem pins 4 and 20 together (effectively doing CTS=DTR), rather
it jumpers modem pins 6 and 20 together (DSR=DTR). This cable also
connects modem pin 8 to Mac pin 7, providing the Mac with the DCD (Carrier
Detect) signal. Note that my documentation fails to state the fact that
Mac pins 4 and 8 are jumpered together (necessary to anchor Rd+, I think).

I also have a Hayes brand cable in service, but since I am using it 
for this connection, I can't ring it down :-). 

Net mavens have told me that the Mac is not able to support all four
hardware handshaking signals simultaneously (those signals are RTS/CTS
(Ready To Send/Clear To Send) and DSR/DTR (Data Set Ready/Data
Terminal Ready). The pinout of the ProModem supports RTS/CTS and klooches DSR/DTR.

The pinout given by Cieman has a different klooch, namely the modem
sees (via its DTR input) that, whenever it asserts its RTS output, the
Data Terminal (the Mac) is ready.

Interestingly enough, the NeXT's serial port is RS-423, rather than
RS-422, as in the Mac. The former supports the four independent handshaking
signals.

Please email me if you have any corrections to these data. I am certain of
the characteristics of the cable, and the assignment of signal names at
the modem end of the cable, but a little uncertain of my interpretation
of the signals' meanings and the assignment of signal names at the Mac end.
Arthur Ogawa        Internet: ogawa@orion.arc.nasa.gov  Ph: 1/415/691-1126
TeX consultant      AppleLink: ogawa                    FAX:1/415/962-1969

russotto@eng.umd.edu (Matthew T. Russotto) (03/25/91)

In article <27EB1B0B.3468@ics.uci.edu> aciemian@ics.uci.edu (Alan Ciemian) writes:
>A few people have requested that I post the cable wiring for a 
>mac DIN-8 to modem w/handshaking.  Thanks and apologies to 
>Software Ventures.
>
>MAC DIN-8        modem 25 pin
>----------------------------------
>pin 1      to    pin 4 and pin 20
>pin 2      to    pin 5
>pin 3      to    pin 2
>pin 4      to    pin 7
>pin 5      to    pin 3
>
>There is also a jumper from pin 4 to pin 8 on the mac side (or also
>connect mac pin 8 to modem pin 7.
>
>
>To adapt a standard cable at the modem end wire an adapter as follows:
>
>
>mac side    modem side
>-----------------------
>pin 2      to pin 2
>pin 3      to pin 3
>pin 5      to pin 5
>pin 7      to pin 7
>pin 20     to pin 20
>pin 20     to pin 4

This is not a flame, merely a correction:
You don't want pin 20 connected at the modem end at all.  Pin 20 is Data
Terminal Ready, and many modems will not accept commands if it is low,
and will hang up if it is dropped.  Thus, the cable will work fine--- UNTIL
handshaking is used, at which point the mac TRIES to tell the modem not
to send any more, but instead tells it to hang up.  So don't connect pin 20
at all, and set the modem to ignore terminal DTR (usually a dipswitch).

The adaptor cable allows only one-way handshaking from the modem to the mac
if the DTR is not a problem.  To allow two way handshaking with most cables,
pin 8 on the mac side should be connected to pin 5 on the modem side (most
cables are set up so pin 8, carrier detect, goes to handshake in).  Pin 20
(Mac side) should go to pin 4 (modem side) ONLY-- not pin 20 (modem side)

If you like, with the regular cable (not the adaptor), connect pin 7 (mac
end) to pin 8 (modem end), to allow carrier detect on the general-purpose
input (if your software supports it-- most doesn't)
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.

russotto@eng.umd.edu (Matthew T. Russotto) (03/25/91)

In article <1991Mar24.082806.14851@news.arc.nasa.gov> ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:

>The pinout given by Cieman has a different klooch, namely the modem
>sees (via its DTR input) that, whenever it asserts its RTS output, the
>Data Terminal (the Mac) is ready.

Unfortunately, Pin 4 is TO the modem-- so what the modem sees is that whenever
the mac is ready to recieve (CTS asserted), the Data Terminal is ready.  This
is bad, as I pointed out in another post.

>Interestingly enough, the NeXT's serial port is RS-423, rather than
>RS-422, as in the Mac. The former supports the four independent handshaking
>signals.
  Pin 20
(Mac side) should go to pin 4 (modem side) ONLY-- not pin 20 (modem side)

If you like, with the regular cable (not the adaptor), connect pin 7 (mac
end) to pin 8 (modem end), to allow carrier detect on the general-purpose
input (if your software supports it-- most doesn't)
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.

russotto@eng.umd.edu (Matthew T. Russotto) (03/25/91)

In article <1991Mar24.082806.14851@news.arc.nasa.gov> ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:

>The pinout given by Cieman has a different klooch, namely the modem
>sees (via its DTR input) that, whenever it asserts its RTS output, the
>Data Terminal (the Mac) is ready.

Unfortunately, Pin 4 is TO the modem-- so what the modem sees is that whenever
the mac is ready to recieve (CTS asserted), the Data Terminal is ready.  This
is bad, as I pointed out in another post.

>Interestingly enough, the NeXT's serial port is RS-423, rather than
>RS-422, as in the Mac. The former supports the four independent handshaking
>signals.

How many pins on the NeXT's port?  In order to support four handshaking
signals, you need at least 9 pins.
(TxD+, TxD-, RxD+, RxD-, CTS, RTS, DSR, DTR, Gnd)
--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.

minich@unx2.ucc.okstate.edu (Robert Minich) (03/25/91)

ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:
: 
|>Interestingly enough, the NeXT's serial port is RS-423, rather than
|>RS-422, as in the Mac. The former supports the four independent handshaking
|>signals.
 
by russotto@eng.umd.edu (Matthew T. Russotto):
| How many pins on the NeXT's port?  In order to support four handshaking
| signals, you need at least 9 pins.
| (TxD+, TxD-, RxD+, RxD-, CTS, RTS, DSR, DTR, Gnd)

Not if you don't use differential signals.
-- 
|_    /| | Robert Minich            |
|\'o.O'  | Oklahoma State University| "I'm not discouraging others from using
|=(___)= | minich@d.cs.okstate.edu  |  their power of the pen, but mine will
|   U    | - "Ackphtth"             |  continue to do the crossword."  M. Ho

ogawa@orion.arc.nasa.gov (Arthur Ogawa) (03/25/91)

In article <XRgaZ3w162w@alchemy.tcnet.ithaca.ny.us> sethcohn@alchemy.tcnet.ithaca.ny.us (seth cohn) writes:
|aciemian@ics.uci.edu (Alan Ciemian) writes:
|> A few people have requested that I post the cable wiring for a 
|> mac DIN-8 to modem w/handshaking.
[lines deleted]
|not to press a point BUT that cable will not do carrier detect at all
|since no pin is left to use with DCD (carrier detect - pin 8 of db25)
|
|I think it's ridiculous that the mac won't do Handshaking AND carrier 
|detect at the same time.  Gimme a good db25 for the mac.

I recently posted the pinout of the modem cable for Mac that came with
my Prometheus ProModem. It did include provision for DCD, namely Mac
mini-DIN-8 pin 7 to the modem (DCE) DB-25 pin 8.

I have now checked out my Hayes-brand cable (which I bought expressly to 
go with a borrowed Telebit T2500). It is identical to the Prometheus
cable, except it does _not_ provide for DCD.

Arthur Ogawa        Internet: ogawa@orion.arc.nasa.gov  Ph: 1/415/691-1126
TeX consultant      AppleLink: ogawa                    FAX:1/415/962-1969
Arthur Ogawa        Internet: ogawa@orion.arc.nasa.gov  Ph: 1/415/691-1126
TeX consultant      AppleLink: ogawa                    FAX:1/415/962-1969

russotto@eng.umd.edu (Matthew T. Russotto) (03/27/91)

In article <1991Mar24.234125.7088@unx2.ucc.okstate.edu> minich@unx2.ucc.okstate.edu (Robert Minich) writes:
>ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:
>: 
>|>Interestingly enough, the NeXT's serial port is RS-423, rather than
>|>RS-422, as in the Mac. The former supports the four independent handshaking
>|>signals.
> 
>by russotto@eng.umd.edu (Matthew T. Russotto):
>| How many pins on the NeXT's port?  In order to support four handshaking
>| signals, you need at least 9 pins.
>| (TxD+, TxD-, RxD+, RxD-, CTS, RTS, DSR, DTR, Gnd)
>
>Not if you don't use differential signals.

Then how is it different from regular RS-232?

--
Matthew T. Russotto	russotto@eng.umd.edu	russotto@wam.umd.edu
     .sig under construction, like the rest of this campus.

sethcohn@alchemy.tcnet.ithaca.ny.us (seth cohn) (03/27/91)

ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:

> In article <XRgaZ3w162w@alchemy.tcnet.ithaca.ny.us> sethcohn@alchemy.tcnet.it
> |aciemian@ics.uci.edu (Alan Ciemian) writes:
> |> A few people have requested that I post the cable wiring for a 
> |> mac DIN-8 to modem w/handshaking.
> [lines deleted]
> |not to press a point BUT that cable will not do carrier detect at all
> |since no pin is left to use with DCD (carrier detect - pin 8 of db25)
> |
> |I think it's ridiculous that the mac won't do Handshaking AND carrier 
> |detect at the same time.  Gimme a good db25 for the mac.
> 
> I recently posted the pinout of the modem cable for Mac that came with
> my Prometheus ProModem. It did include provision for DCD, namely Mac
> mini-DIN-8 pin 7 to the modem (DCE) DB-25 pin 8.
> 
> I have now checked out my Hayes-brand cable (which I bought expressly to 
> go with a borrowed Telebit T2500). It is identical to the Prometheus
> cable, except it does _not_ provide for DCD.
> 
> Arthur Ogawa        Internet: ogawa@orion.arc.nasa.gov  Ph: 1/415/691-1126
> TeX consultant      AppleLink: ogawa                    FAX:1/415/962-1969
yes, SOME cables are wired for DCD, BUT Some MACs won't do it (like the 
plus, classic, lc and possibly the SI (heard one person say it worked, 
butthe APPLE manual says NO)
Pin 7 isn't connected!!!  anyone know anyway (even a HARDWARE job!) to 
get the mac plus to do Carrier detect AND handshaking.  I've got 2 9600 
baud modems on my bbs, and I need both carrier detect AND handshaking.

Seth

Seth Cohn, Service Tech.  607-273-2815 voice 607-272-7002 BBS
All things posted are opinions by me, of me, for me, or to me.
And another thing..........I'm not sure you're real.

kpmiller@uokmax.ecn.uoknor.edu (Kent P Miller) (03/28/91)

In article <uL7FZ4w162w@alchemy.tcnet.ithaca.ny.us> sethcohn@alchemy.tcnet.ithaca.ny.us (seth cohn) writes:
>ogawa@orion.arc.nasa.gov (Arthur Ogawa) writes:
>
>> In article <XRgaZ3w162w@alchemy.tcnet.ithaca.ny.us> sethcohn@alchemy.tcnet.it
>> |aciemian@ics.uci.edu (Alan Ciemian) writes:
>yes, SOME cables are wired for DCD, BUT Some MACs won't do it (like the 
>plus, classic, lc and possibly the SI (heard one person say it worked, 
>butthe APPLE manual says NO)
>Pin 7 isn't connected!!!  anyone know anyway (even a HARDWARE job!) to 
>get the mac plus to do Carrier detect AND handshaking.  I've got 2 9600 
>baud modems on my bbs, and I need both carrier detect AND handshaking.
>Seth
Great, Seth.  No you've done it.  Here I sit reading news on my MacIIsi, and
you go and tell it It can't do Hardware Handshaking.  No more V.42 for me, 
no sir.  Thanks to you.
:)
Kent

-- 
-----------------------
Kent Miller
KENT@aardvark.ucs.uoknor.edu
Bitnet -> KENT@uokucsvx