Can you tell me all the connections you have made between the jrk and the uLCD-32PT?
Do you have an oscilloscope available?
For now, I recommend setting the jrk’s serial mode to UART with a fixed baud rate of 9600.
The answer to those questions is yes, but we call it the “compact protocol”, not the “simple mode protocol”. You should give the jrk several milliseconds to start up before sending the 0xAA byte. However, I recommend not using auto-baud detect for now because it introduces another layer of complexity and possible issues.
The Jrk Configuration Utility uses the jrk’s native USB interface, which is different from its serial interfaces. I’m not sure what page of the documentation you were reading, but it probably was only talking about the serial interfaces.
You should give the jrk some time to initialize itself after powering on or else it might lose the first few bytes you send to it. One hundred milliseconds should be more than enough time. We don’t have any specs on how long it takes the jrk to respond to serial commands but it should be pretty fast. Not all commands result in a response. Before you worry about receiving bytes from the jrk, we need to fix the Serial Signal Error you are getting.