The RF system doesn't use the same protocol, it's a new protocol (to potentially hack and reverse-engineer).

The early shelf-label systems were IR-based, sold in bulk and were programmed manually using handheld devices held against them.

Most shelf-label solutions of today are part of a service-model, where gateways are mounted in the store to wirelessly update any label on price-change, often orchestrated remotely so store-chains can update all shops simultaneously.