According to the manual...
If that doesn't work....
Also, here is the link to the firmware if you think it needs to be reloaded for some reason. Download the zip file and open the Readme document for directions.
So I would try 38400 speed and see what they reply is.The serial port requires 38400-baud, 8 data bits, no parity, 1 stop bit, with Xon/Xoff flow control
enabled. 38400 is recommended, but 1200 to 115200 is available via a configuration command.
If that doesn't work....
I would try that and then connect at 9600.You can also force the system to 9600-baud by holding the rear-panel Memory-Erase button depressed as you apply power.
This provides a quick field change to 9600 for systems that cannot reach 38400-baud (notably some Vantage controllers).
Also, here is the link to the firmware if you think it needs to be reloaded for some reason. Download the zip file and open the Readme document for directions.