Printer toner cartridges are designed with specific page yields. Nowadays laser printers or copiers usually use a toner chip (also called a smart chip) to monitor and count the pages used during printing. The toner chip is connected to the printer via direct contact or non-contact (RF). It is usually gold with a small PCB board and is dedicated to the storage unit for data storage, sometimes configured with the processor to respond to the request of the processor or copier. If a particular page is swallowed, it will contact your computer to alert you.