Electronic shelf label

An electronic shelf label (ESL) system is used by retailers for displaying, typically on the front edge of retail shelving, product pricing on shelves that can automatically be updated or changed under the control of a central computer server.^[1]

ESL tag modules use electronic paper (e-paper) or liquid-crystal displays (LCDs) to show the current product price to the customer. E-paper is widely used on ESLs as it provides a crisp display and supports full graphic images (typically only black and white) while only needing power during updates, and no power to retain an image. A communication network from the central computer server allows the price display to be automatically updated whenever a product price is changed, in contrast to static paper placards. Wireless communication is needed and must support appropriate range, speed, and reliability. The means of wireless communication can be based on radio, infrared or even visible light communication.^[2] Currently, the ESL market leans heavily towards radio frequency communication.^{[citation needed]}