3COM Etherlink III 3C509-COMBO Network Card
The 3COM Etherlink III 3C509-COMBO is a classic 16-bit ISA network interface card (NIC) that was widely popular during the early to mid-1990s. Its standout feature is the “combo” designation, referring to its ability to connect to an Ethernet network via three different cabling types: 10BASE-T (RJ-45), 10BASE-2 (BNC), and 10BASE-5 (AUI). This flexibility made it a standard choice for both home and business users as they transitioned between different network setups. The card was also known for its “Parallel Tasking” technology, an early form of hardware acceleration that improved data throughput compared to its competitors at the time. Being a jumperless card, its configuration was managed via software (3C5x9CFG.EXE), making it easier to install and set up than older cards with physical jumpers. The 3C509 was a crucial component for enabling networking on many early PC systems running operating systems like DOS, Windows 3.x, and Windows 95. Though now a retro computing collectible, it remains a robust and reliable piece of hardware for vintage computer enthusiasts and those maintaining legacy systems.
System specification
• Model: 3C509-COMBO (later revisions such as 3C509B-C also exist)
• Device Type: Network adapter (NIC)
• Bus Interface: 16-bit ISA (compatible with most ISA slots)
• Data Transfer Rate: 10 Mbps (Megabits per second)
• Connectivity: Wired
• Cabling Types Supported:
o 10BASE-T: RJ-45 connector (for unshielded twisted pair cable)
o 10BASE-2: BNC connector (for thin coaxial cable)
o 10BASE-5: AUI port (15-pin D-Sub connector for thick coaxial cable transceiver)
• Compliant Standards: IEEE 802.3
• Features:
o Parallel Tasking technology
o Jumperless configuration (managed via software)
o Diagnostic LEDs for port status
o Socket for an optional boot ROM
• Operating System Support: DOS, Windows 3.x, Windows 95/98, Windows NT, NetWare, OS/2, Linux, and others
