[GreenKeys] RS-232 COMx to COMy Port Translation Software in VB6

[David Tumey]

In anticipation of the arrival of a restored ASR-33 in the next few months, I wanted to recreate my RTTY station.  I still have an old MFJ-1278 multimode TNC that I used in the past with AFSK RTTY.  The plan is to control the MFJ-1278 with the ASR-33 TTY.  The challenge is:  (1) the lowest baudrate of the 1278 is 300, (2) It must have hardware handshaking (DTR/CTS), (3) It has one stop bit.  On the other hand, the TTY operates at (1) 110 buad, (2) no handshaking and (3) needs two stop bits.
 
I searched for a software translator I could run from my PC but to no avail, so I wrote the needed code in VB6 and it has been performing flawlessly here on the test bench (I use a laptop configured to emulate a TTY).  I am currently using an Edgeport/4 USB to RS-232 interface from Digi (available on eBay).  I connect the MFJ to COM6 at 9600,n,8,1 and the TTY will connect to COM7 at 110,n,8,2.  I have a RS-232 to 20mA loop that I built back in 1983.  So, fingers crossed, the TTY should plug into COM7 and work just fine.  I tested the system with ITTY and some off-air RTTY - works great.  
 
I understand that some USB to RS-232 adapters can be configured to operate at 45,n,5,2 - which should be good for the model 15/28 if I am correct.  When running the software the PC works just like a pass-thru, all data is moved two and from each port (through the built-in buffers).
 
Anyway,  If anyone would like a copy of the VB6 application, please email me directly and I will reply with a .zip file containing all the source code.  This is a great piece of code if you want to hook up an old TNC like the MFJ or KAM and control it through a heavy metal interface.
 
73's
--dave
W5DT
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