3COM Etherlink III 3C509B-TPO Card ASSY 03-0020-010

Buy online your 3COM Etherlink III 3C509B-TPO Card ASSY 03-0020-010 from US e-store Cnc-shopping USA, specialist in CNC machine-tools spare parts.

The 3COM EtherLink III 3C509B-TPO is an ISA Ethernet network adapter designed to restore or provide network connectivity for industrial PCs and PC-based CNC controllers equipped with an ISA bus. It supports 10BASE-T communication via RJ45 for NC program transfers, DNC applications, and network maintenance operations. It is a suitable replacement unit and industrial spare part for legacy installations.

The 3C509B-TPO (Twisted Pair Only) version features a dedicated 10 Mbps RJ45 port using unshielded twisted-pair (UTP) Ethernet cabling. Its 16-bit ISA interface allows integration into older industrial computers installed behind operator panels or inside CNC control cabinets.

This 3COM EtherLink III network card incorporates Parallel Tasking technology, designed to optimize data transfer performance over the ISA bus. It is suitable for legacy computing environments running DOS, Windows 3.1, Windows 95/98, and Novell NetWare, provided the appropriate drivers and configuration utilities are available.

Identified by reference 3C509B-TPO and assembly code 03-0020-010, this USA-origin network adapter is suitable for DNC communication, NC file transfers, network sharing, and remote diagnostics on existing machine tools and industrial PCs.

The 3COM 3C509B-TPO is a practical CNC replacement component, emergency spare, or refurbished unit for maintenance and retrofit applications. It allows technicians to replace a defective ISA network interface without modifying the original computer architecture, helping minimize production downtime and avoid complex software migrations. Before replacement, ISA bus compatibility, hardware settings, and operating system driver support should be verified.

Each unit supplied by Cnc-shopping can be tested on appropriate PC/ISA test benches to verify functionality and network connectivity. Products are packed using ESD-safe protective materials and industrial-grade packaging, with a commercial warranty under our standard terms.

Cnc-shopping can supply the 3COM EtherLink III 3C509B-TPO as a tested unit, spare part, or refurbished network card, with fast worldwide shipping subject to availability. We also assist with sourcing obsolete parts and may offer repair or exchange services to help extend the service life of existing CNC installations.

Frequently asked questions about 3C509B-TPO:

What interface and speed does this card provide?
It is a 16-bit ISA network adapter that provides a 10BASE-T Ethernet link over RJ45 at 10 Mbps for legacy industrial PCs and CNC controllers.

Is the TPO version suitable if my system only has twisted-pair cabling?
Yes. TPO stands for Twisted Pair Only, so this variant offers only the RJ45 port and is ideal when coax or AUI connections are not used.

Will it work in older DOS or Windows NT-based CNC HMIs?
This series is widely used in DOS and early Windows environments commonly found in legacy CNC PCs. Use the appropriate driver package for your operating system build.

Can it replace other 3C509B variants in a drop-in manner?
If your existing installation uses the RJ45 port, the TPO variant is typically a drop-in replacement. Match resource settings and drivers to the original card to streamline the swap.

Does it fit any ISA slot in an industrial PC?
The board is intended for a 16-bit ISA slot commonly found on legacy backplanes and controller PCs. Ensure mechanical clearance within the enclosure before installation.