Kitchen printer vs display system
A KDS is essentially a modern version of a kitchen printer, because the primary function is the same: to communicate orders front-to-back of house in the kitchen.
Kitchen printers are connected (via cable or wireless LAN) to the point of sale system. When an order is accepted at the till, the kitchen printer produces a paper ticket with information of what to cook and prepare. Someone might have the role to shout out what the order says to prompt the relevant cooks to prepare specific foods.
Such a printer needs to be heat-resistant, since it is based in a kitchen that tends to get warm. You’ll need a supply of receipt rolls and ink rolls so it never runs out while busy.
Kitchen display systems provide a live overview of all orders on a digital screen, not paper tickets. It typically has additional, useful functions to smoothe operations in the kitchen, for example recipe lookup and analytics to identify production bottlenecks.
A KDS is usually installed on a tablet (iPad, Android), but some software may be compatible with purpose-built touchscreens or computer screens. The tablet and software could be more expensive than a heat-resistant printer, but then you don’t need to restock on paper rolls.