Thank you. I found another thread "Loop Back Test - Sticky?" that suggest holding the processor in reset while using terminal. Would this be an effective way of testing Tx Rx on pins 10 & 11?
Disable the processor. The best option is to remove the processor from the board (with the power removed). If you cannot or would prefer not to remove the processor, connect a jumper wire between RESET and GND. This will hold the processor in reset preventing it from running.
Jumper TX to RX.
Apply power to the board. Connect the board to the computer. After a brief pause, Windows should produce a device insertion tone. Linux may or may not produce a device insertion tone; an entry will be added to the system.Start your favourite terminal application. Serial Monitor will work fine.
Ensure your terminal application is connected to the correct serial port. The baud rate is irrelevant.
Type. As you type, the characters should be echoed to the screen. Note: To send data, some terminal applications, like Serial Monitor, require pressing the Enter key or clicking a Send button.