Table status

How do you notify the kitchen that a table's ready for the entree?
Someone who works in the hospitallity business told me about working with coloured keychains.

If a table is ready for let's say the entree the waiter hangs a green keychain with the tablenumber on it on a board so kitchen nows they can start preparing the entree.
When they are done they place the platter on the 'distribution counter' with the keychain next to it.

How would you automate this process?
Would it be handy if I create some kind of panel with all the tables on it and you could change the status by changing colour (e.g. apetizer=green, entree=red, dessert=blue)?



Waiters could change the table status and depending on the status the printers in the kitchen would print the orders needed...

If you have an idea, please leave a comment?