serial port adapter problems on Mac

hey guys i have a problem with my serial port adapter i can seem to get the imac to reconize it i even uploaded the driver. i am trying to get fta bevs onto my sat box i have to program loader on there and have unzipped the files. i just cant get to computer to reconize my serial port adapter. do guys know if i can find another adapter that has a driver that will work on the imac with mac os x. i think thats my problem my serial port adapter is only pc based. if u guys know a mac one send me a link so i can buy or let me know a store or if i can use the other one with some steps thanks