A physical link providing electric continuity across an individual cell in the memory array of a PROM. With this link intact the cell,when interrogated, will display a known logic state. During programming this link can be destroyed, forcing the cell to take on the complementary logic state; this process is irreversible. Fusible links are used in a similar manner in field-programmable logic arrays (see PLA). A fusible link is sometimes incorporated in a PROM or PLA to ensure that the data cannot be changed after being programmed. A similar technique is employed in some printer consumable items (e.g. toner cartridges) to ensure that they are not re-used.