The Serial LCD board communicates at 57600, 38400, 19200, 9600, 4800, 2,400 or 1,200 Baud. It uses 8 data bits, no parity and 1 stop bit. There are no switches or jumpers to set the baud rate. See this from the datasheet in post #1:
It has a unique feature called AutoSYNC that will automatically adjust to the baud rate of the incoming data.
When the display is powered-up (and after waiting for it to settle and the splash screen to appear), send the
character “U” [85] and the display will automatically set its baud rate within about 500mS (the splash
screen will change from “AutoSYNC” to “Connected” when this is accomplished).
Clicking on the "CONNECT" button (see previous post) does this - it sends out the character "U".