If your cable is a more affordable version, it likely uses a Prolific PL2303 chipset. Drivers are usually available through Prolific's official support.
Remember that AWM 20251 is for voice and low-speed data . It cannot be converted into high-speed Ethernet (Cat5/Cat6) because it lacks the necessary twisted-pair construction to prevent interference at high speeds. If you're still having trouble, let me know: awm 20251 driver