Re: null-modem connection IIC/ PC: Verifying pin assignment / 'Shorting' wires question!

[Rubywand <rubywand@swbell.net>]

Aage Rettvin writes ...
> 
> With reference to received  advice on the newsgroup I have looked into the
> pin-assignments as given in the French Apple IIc .dsk site:
> 
> Rubywand wrote:
> 
> >
> >http://www.multimania.com/apple2c/tech/Transfert.htm
> >
> >The Apple IIc .dsk Archive site seems to be using this numbering on the
> DIN-5 connector.
> >
> >1        3
> > 4     5
> >     2
> 
> ----> I've constructed a new shielded five-lead
> cable with the following PIN
> assignment setup:
> 
> DIN-5F    ----> DB9F
> 
> #3  DTR           #6
> #5  TX             #2
> #2  GRN          #5
> #4  RX             #3
> #1  DSR           #4
> 
> -----> The cable is not working properly as there lacks some modifications
> according to feedback from  from  delfs@apple2.com  who wrote following:
> 
> >because the IIc does not do hardware handshaking, you must
> >cross the wires on the AT class machine so it'll transmit.
> >Short 6,8 and 20 on
> >the 25 pin serial port or 1, 6 and 4 on the 9 pin version to get the dos
> >transfer to work. This effectively tells it that it is OK to transmit and
> >recieve.
> 
> ---->How should the 1,6 and 4 be 'shorted' on the DB9F,  the leads
> themselves or directly on the socket.  Pls. update me
> on how to do this as I
> am not familiar with the terms used here!
 ....

    "Shorting" here just means the pins are connected by a jumper. (For
example, on the 9-pin connector you would jumper pins 1 and 6. The line
coming from pin 1 of the 5-pin DIN connector would connect to either of the
jumpered pins.)
 
     Let's list the French //c NULL modem cable for ADT showing all signal
names and signal directions. (The DIN-5 connector shown is the plug on the
cable.)  I'll put traditional Apple pin numbers in parenthensis ...

  DIN-5M            Dsub9   or    Dsub25
 (Apple)            9 pins        25 pins
 
 4 (2) TXD     -->  2 RXD         3 RXD
 5 (4) RXD     <--  3 TXD         2 TXD
 2 (3) GND     ---  5 GND         7 GND
 1 (1) DTR     -->  6 DSR --,*    6 DSR --,*
                    1 DCD --'     8 DCD --'
 3 (5) DSR/DCD <--  4 DTR        20 DTR

* pins connected by a jumper


     Usual Apple numbering for a male cable connector (plug) as viewed
looking at the pins from the front is ...


1       5
 2     4
    3


     Showing only the usual Apple numbering and a Dsub9 connector going to
the PC, the French //c ADT NULL modem cable pinout would be ...


   Apple           Dsub9  
  "DIN-5M"         9 pins 
 
   2  TXD     -->  2 RXD  
   4  RXD     <--  3 TXD    
   3  GND     ---  5 GND  
   1  DTR     -->  6 DSR --,*
                   1 DCD --' 
   5  DSR/DCD <--  4 DTR 

* pins connected by a jumper

     Whether the Dsub9 connector is male or female depends upon what it needs
to plug into.

     Be sure to post something about how this works.



Rubywand