DC242 do not have metered or sold toners.
006R01451 is double pack (2 toners in one box)
006R01221 is single pack

Newer machines (dcp700,770, c75, j75,c550,c60) have metered and sold toners (west europe and USA and DMO)
If machine is set for metered toners it can work with all type of toner.
If machine is set for sold, then it can use only Sold DMO or SOLD USA/WE