IBM 39F8370 8-Bit ISA Token Ring Network Adapter Card PC LAN 4Mbps 16Mbps

IBM 39F8370 8-Bit ISA Token Ring Network Adapter Card PC LAN 4Mbps 16Mbps

The IBM 39F8370 is an 8-bit ISA Token Ring network adapter designed for IBM PCs and compatible systems equipped with an 8-bit ISA expansion slot. It connects workstations to IEEE 802.5 Token Ring local area networks at 4 Mbps or 16 Mbps, depending on the ring configuration. The card uses a DB9 (DE-9) bracket connector for attachment to the Token Ring lobe cable.

Specifications & What's Included

• Manufacturer: IBM
• Part Number: 39F8370
• Board Assembly Number: 2330361
• PCB Marking: 39F8370 90 370 AZX
• Bus Interface: 8-bit ISA
• Network Technology: IEEE 802.5 Token Ring
• Data Rate: 4 Mbps / 16 Mbps
• Bracket Connector: DB9 (DE-9) Token Ring lobe port
• Notable ICs (visible on PCB): SN74LS125AN (x2), MS9012C (74F32PC), FFBC9008 (x2)
• Country of Manufacture: Malaysia (per PCB label)
• Included: Card only — no cables or accessories

Applications

Token Ring was IBM's proprietary local area network technology, introduced in 1984 and standardized as IEEE 802.5. It used a deterministic token-passing protocol rather than the collision-based CSMA/CD method of Ethernet, which gave it predictable, low-latency performance valued in environments where consistent throughput mattered — such as manufacturing floors, banks, and IBM-centric corporate networks of the late 1980s and early 1990s. 8-bit ISA Token Ring adapters like this 39F8370 were used in IBM PC, PC/XT, and compatible machines to connect those workstations into Token Ring LANs running IBM operating environments such as PC-DOS, OS/2, and early LAN Server deployments. By the mid-1990s, Fast Ethernet had displaced Token Ring in most new installations, but large IBM-installed-base organizations continued running Token Ring infrastructure well into the 2000s. Today this card is primarily sought for maintaining or restoring vintage IBM PC-era networks, for computer history collections, and for legacy industrial or process-control environments that still run Token Ring segments.