Unfortunately we no longer have the units. We changed our app to not query the LCD and shipped the units. We now only have the newer displays in stock...

This seems to be just the request serial number function (which I notice was dropped in the updated LK402-25 product) and the request firmware version (for which the 402-25 product says only works in TTL mode) Were these features dropped prematurely? These particular units were near the end of the ...

We use LK402-12 displays in a product and have several units that after setting the serial number the lcd stops sending information back. Setting the serial number may not be relevant.
Our test program sets up the serial port, then reads the module type and determines the configuration. After we ...