When a system operator either upgrades to digital/analog from analog, or when they change from one proprietary brand of box to another, that forces the customer to get a new box from the operator. Thus it's called a forced swap. Forced swaps are usually better paying overall for box-placement contractor because they don't have to overcome sales resistance. If the customer wants to receive the premium services they have to have the new equipment.
This is CABL.com posting #54822. Tiny Link: cabl.co/moqo