Scheduling coordinators (SCs) submit balanced schedules and provide settlement-ready meter data to the ISO. Scheduling coordinators also: Settle with generators and retailers, the PX and the ISO; Maintain a year-round, 24-hour scheduling center; Provide non-emergency operating instructions to generators and retailers; Transfer schedules in and out of the PX. (The PX is a marketplace. As bids are accepted, power is being bought and sold. Once a bid is accepted, the power sold is "transferred out" of the PX, since is it no longer available. Power that is available for sale is "transferred in" to the PX. These transfers may also take place directly between the buyer and seller, without involvement of the PX.) The PX is considered a scheduling coordinator.