PRO Null Modem Transfers

From: Michael Current (aa700@cleveland.Freenet.Edu)
Date: 01/16/92-05:52:27 PM Z


From: aa700@cleveland.Freenet.Edu (Michael Current)
Subject: PRO Null Modem Transfers
Date: Thu Jan 16 17:52:27 1992




                    PRO Null Modem Transfers

                            1-17-90

                         Circular Logic
                          718-351-4304

It has recently come to our attention that many Pro SysOps are having
difficulty establishing a Null Modem transfer between their BBS and
a second computer, be it ST, IBM or XL.

It is quite easy and reliable as long as the correct cable is used.

The correct pinouts are as follows:

Note: should you mess this
up and blow up yourself or your neighborhood
we assume _no_ responsiblity! Get your pins right! They are labled
on any decent brand of connector. Here are views looking at the
'business' ends of the connectors-

Male DB9                        Female DB25
1 2 3 4 5          13 12 11 10 09 08 07 06 05 04 03 02 01
 6 7 8 9             25 24 23 22 21 20 19 18 17 16 15 14

   
Atari 9 pin  to    Atari 9 Pin    or   IBM/ST 25 pin
____________       ___________          __________
1 DTR  *               1                   20 Data Terminal Ready *
2 CRX  *               2                    8 Data Carrier Detect *
3 XMT                  4                    3 Recieve Data
4 RCV                  3                    2 Transmitted Data
5 GND                  5                    7 Signal Ground
6 DSR                  6                    6 Not Connected
7 RTS                  7                    4 Request To Send
8 CTS                  8                    5 Clear To Send
9 NOT CONNECTED----------------------------------------------------

*** Note IMPORTANT inorder to work with Pro and or Express, Tie
(short) pins one and two (DTR/CRX) together on the XL end
(and/or pins 8 & 20 on the ST/IBM end) This insures a Carrier
Detect for the BBS.  
*Note: The only lines really needed are the lines on pins 1-5 on the
XL end
 (WITH the pin 1 & 2 mod as above). This swaps the Send/Recieve
lines and forces a carrier detect for the BBS and grounds both 
systems.

After hooking up the cable and matching baud rates (BAUD.CMD by
Circular Logic serves nicely to temporarly step up your
BBS baud rate for a null modem transfer) bang on the RETURN key
on the remote system untill the BBS 'sees' the keypress and
starts the normal logon process.
Programs tested to work on the remote are: 850 Express, 
Express Cart,Flash, DualTerm, Procomm Plus.  
           -Hope this helped!                        -Tom & Bill


------------------------------------
I have not built the cable YET, so I don't know if it works for sure.

Bob


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 Michael Current, Cleveland Free-Net 8-bit Atari SIGOp   -->>  go atari8  <<--
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