If all the voltages are correct as I have given,
1) with no signal at R1IN, what is the voltage at R1OUT? It should be 5V.
2) with R1IN at 5V, what is the voltage at R1OUT? It should be 0V.

 

I have since used a new known working sketch and am getting the same result, it can tx a "hi" to the terminal just fine, I'm supposed to be able to type a lowercase letter and get an uppercase back but I get nothing, I can see the data going to the 232 side on the scope when I kit the key but nothing on the TTL side despite the 10k resistor test working.

 

Is the trigger input and trigger level on the oscilloscope set correctly?
Set the trigger level to +1V.

 

Yes it is at 1V, I can have the scope on the TTL tx press reset and see the data, "hi" appears in terminal, and the scope triggers on it, I move scope to Rx press a key and nothing, then move scope to rs232 Rx, press a key and see the data there at rs232 levels

 

If all the voltages are correct as I have given,
1) with no signal at R1IN, what is the voltage at R1OUT? It should be 5V.
2) with R1IN at 5V, what is the voltage at R1OUT? It should be 0V.

I have completed this testing as well and I do see ROUT drop to 0V when RIN is 5V

 

Maybe I don't understand your test.

Connect CHAN1 of the oscilloscope to R1IN, 5V/DIV. Trigger on CHAN1, with a trigger level at +1V.
Connect CHAN2 of the oscilloscope to R2OUT, 5V/DIV.

You should be able to see CHAN2 swing from 0V to +5V in sync with CHAN1 but inverted.

 

This is the issue, no output what so ever, everything has been ohmed out 5 times to ensure I'm on the right pins, no matter what there is just nothing there, enable pin is low, shutdown is high. Just did the test, here is the scope shot.

 

Let us focus on one thing at a time and examine what the oscilloscope is showing.
We can still get to the bottom of this.

When the MAX242 is not connected, the RS-232 TD signal swings from -7.5V to +7.5V as shown in post #9 and #11.

When the MAX242 is connected, the RS-232 TD signal as seen at R1IN or R2IN is different from before? In other words, it should still swing from -7.5V to +7.5V.
(Ignore R1OUT and R2OUT for the moment.)

Show a photo of how your oscilloscope probe tip and GND clip are connected to your test circuit.

 

Look to be the same connected and not connected to MAX242

Disconnected


Connected

 

No. The scope is showing something differently.
Now it is showing the signal swinging between 0V and +16V which is now totally different from before.

Where is the oscilloscope GND clip connected?

 

From what I observe, your GND connections are not consistent.
Check all GND connections

PC GND
Arduino GND
+5V supply GND
MAX242 GND
Oscilloscope GND

Check those grabber hookup jumper cables. They often go bad.

 

From what I observe, your GND connections are not consistent.
Check all GND connections

PC GND
Arduino GND
+5V supply GND
MAX242 GND
Oscilloscope GND

Check those grabber hookup jumper cables. They often go bad.

You nailed it, PC ground was not common, serial adapter ground was 5, was using 7, corrected this and all is working. I cannot thank you enough for this guidance. It is very much appreciated, and I have learned a lot Thank you so much.

Final scope shot

 

You nailed it, PC ground was not common, serial adapter ground was 5, was using 7, corrected this and all is working. I cannot thank you enough for this guidance. It is very much appreciated, and I have learned a lot Thank you so much.

You are very welcome. Glad you found the problem. Never discard the thought that it is a simple problem.
The other important lesson is that it is important to try and resolve the issue and not try to rip things apart and start over again.
You learn more by finding and correcting your mistakes than getting things working right the first time.

 

Agreed, lots of life lessons learned on the bench! Here is the finished prototype