Hi all

I'm trying to interface a serial LCD by byvac with keypad via HSERIN/OUT
http://www.byvac.com/index.php/BV4619
but have the following problem

If I want to read a "keypress" ,following the datasheet i need to send:

rg(carriage return)
if no key is pressed i get the following back from the LCD module 0ack in hex (30 06)
if a key is pressed it returns 4 bytes example key 1 pressed it returns 238ack (hex 32 33 38 06)

how can i handle for eaxmple the STR hserin function to check if a key is pressed = 4 bytes returned or unpressed 2 bytes returned

Thanks