Esp32-DevkitC-V4 cannot get serial port to work

[DickKey1]

I'm using Windows 10. The Esp32-DevkitC-V4 has an Esp32-WROVER-IE module on it. Using Esp32 Flash Download Tool V3.9.5 and flashing factory_WROVER-32.bin into the kit. I get a log message that says "Download Results: PASS". I then hook up another PC USB port through a DSD TECH converter board running at 3.3V. I run TXD from this board to my Esp32-Devkit to pin 36 which is indicated as the RXD input, and I run RXD from the converter board to the Esp32-Devkit to pin 31 which is indicated as the TXD output. I am following the ESP32, ESP-AT User Guide instructions to do all of this. I am using the suggested serial terminal SecureCRT 9.4 and believe I have set it up properly, 115200, 8, none, 1 and Rx/Tx for flow control. I issue the suggested command AT+GMR but I receive no response. If I hit the reset button on the Devkit, I do get "ready" on the terminal. But I see no other responses to any AT commands I send. I have used serial terminals a lot in the past and can't see what I might be doing wrong, hopefully something simple! I have two each of the WROVER dev kts and two of the DSD TECH converter boards. They all give the same behavior, that is, no response to issuing the AT commands. Any suggestions on what could be going wrong?

Thanks,