You are correct, I clicked on the wrong link when I was looking at dataseets yesterday. As I mentioned earlier, the circuit was working for quite awhile so I made a few boards. Now I see there are some problems with a few other PC's. Back to my original question, if 16780 works for 2400 baud in a SER2 command, what is the True seeting? I tried 396, then I get something other than what I expect. Looks like a baud rate setting. I can remove the MAX8130 and the circuit works fine, when the SER2 commands are returned to the proper settings. Thanks for pointing out the USART pins. Unfortunately, I have made boards and those pins are used.

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