Re: Problem with null modem for Apple IIc

[Rubywand <rubywand@swbell.net>]

Your name writes ...
> 
> Hi,
> 
> I am having a problem getting a null modem to work between my Apple IIc
> and my laptop PC.  I hope someone can help me solve this problem.
> 
> I want to use the null modem to run ADT, but I keep getting I/O errors in
> ADT.  I created my null modem cable according to the following pinout:
> 
> DIN-5, male       DB9, female
> (Apple)
> 
> 4 (2) TXD     --> 2 RXD
> 5 (4) RXD     <-- 3 TXD
> 2 (3) GND     --- 5 GND
> 1 (1) DTR     --> 6 DSR --, pins 6 and 1 connected by jumper
>                   1 DCD --'
> 3 (5) DSR/DCD <-- 4 DTR
> 
> The pin numbering that I used for the DIN-5 connector, as viewed by
> looking at the pins on the front, are:
> 
> Apple numbering      Standard numbering
> 
> 1     5                  1     3
>  2   4                    4   5
>    3                        2
> 
> The pin numbering that I used for the DB9 end of the null modem cable, as
> viewed by looking  at the front of the female connector, are:
> 
> --------------
> \ 5 4 3 2 1 /
>  \ 9 8 7 6 /
>    -------
> 
> This is what happens when I install the null modem cable, and I boot up
> Windows 3.11 (on the PC) and ProDOS (on the Apple IIc).
> 
> If I type IN#2 on the apple, I can enter text in a terminal emulator and
> the text will display perfectly on the Apple IIc monitor.
> 
> However, if I type PR#2 (print to the serial port) when I type something
> on the Apple, I get gibberish on the teminal emulator (ion the PC sode).
> The gibberish looks like this:
> 
> ����ç??������� ����Ò?�Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?�
> �Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?Ý?�ì»?�������� ����Ò?��ì»?�������� ����Ò?��ì»?��
> ������ ����Ò?��ì»?�������� ����Ò?��ì»?�������� ����Ò?���ê??�
> ������ ����Ò?������������������������������������������������������������
> ��������������������������������������ô??¿ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ ����Ò?�Ý?Ý?Ý?�����ê??�
> ������ ����Ò?�����������������è??������ ����Ò?���������������������������
> ����������������������������æ??������������������������������������������
> ������ê??������� ����Ò?��
> 
> The serial port settings on both sides are the same, and I'm running at
> 300 baud.
> 
> Does anybody know what I am doing wrong, ar have a suggestion that will
> help me.  It appears that I can send text from the PC to the Apple IIc,
> but CANNOT send text from the Apple IIc to the PC.
> 
 ....

     It looks like your cable is wired correctly and your setup is working the
way it should. 

     You can get rid of the high bit and get the right characters on the PC
side by telling your PC terminal program to force 7-bit ASCII on received data.
In Hyperterm, you go to Properties, click on Settings, and click on ASCII
Setup, to get to the setting. (Which is fine for Text. Don't think you'd want
that setting for transferring files, though.)

     Instead of doing a PR#2, you can get into a dumb terminal mode by doing
...

IN#2
CTRL-A T (Control-A --- you see a ?-- followed by pressing T) for Term mode
CTRL-A I  to echo characters you type on the IIc
CRTL-A R  to reset port and exit serial Port 2 firmware


     I don't know why ADT should not be working. Have you tried a higher baud
rate, like 2400?

     You could check the ADT you transferred to your Apple IIc using a short
program which does a checksum test. You can find a listing in the file
ADTcheckJUL2000.txt at http://apple2.org.za/gswv/a2zine/Utils/ .



Rubywand