3Com EtherLink III ISA - network adapter in excellent condition and fully tested under Windows 2000 Server - working normally. This is the 3C509 version of the card from 1992 featuring two different connectors for thicknet and thinnet networks, but not Twisted Pair or Plug and Play, PnP came along much later.

3Com EtherLink 10 Mbps Desktop NICs Features and Benefits per old 3Com website

Feature Benefit
Compatibility and Reliability
IEEE 802.3 compliance Provides full compliance with global Ethernet standards.

Guaranteed compatibility Guaranteed compatible with respective PCI, ISA, EISA, and MCA bus-compliant systems or your money back. Also compatible with leading network operating systems and applications in a wide range of LAN environments.

Lifetime limited warranty* Backed by 3Com's industry-leading lifetime warranty.

Highly integrated design Combines the Ethernet controller, twisted-pair receiver, encoder/decoder, bus interface, and packet buffer memory on a single ASIC chip to deliver reliable, trouble-free operation and lower cost.
Performance
Parallel Tasking® technology Pipelines data for highest throughput at 10 Mbps.

Parallel Tasking II technology
(ISA and PCI models only)
Lowers CPU utilization and increases application performance due to more efficient data transfer across the PCI bus.

32-bit bus mastering DMA
(ISA and PCI and EISA models only)
Offers a wide data path and fast transfers with low CPU utilization to provide optimum system performance.

Flow Control 802.3x Delivers higher performance due to more efficient data transfers. Optimizes data transfers by reducing lost packets and retransmissions when the NIC communicates with the switch

TCP/IP Checksum Offloads the CPU by performing checksum on ASIC to significantly reduce CPU utilization (OS dependent—functional with Windows NT 5.0).

Traffic prioritization
(ISA and PCI models only)
Uses the IEEE 802.1p standard to prioritize time-sensitive data and improve the performance of multimedia and business-critical applications.

Performance monitoring
(ISA and PCI models only)
Enables comprehensive, low-cost network management in switched and high-speed networks using RMON-1/RMON-2 for application response time and system-level monitoring.

Efficient Multicast Control (ISA and PCI models only) Uses the IEEE 802.1p GMRP standard to improve network performance by controlling multicast flooding in switched LANs

Remote Wake Up (RWU)
[3C900B-FL(ST) only]
Lowers your cost of ownership with remote and after-hours maintenance of PCs with a 3-pin RWU connector and a desktop management application that generates a Magic Packet™ RWU signal.

ACPI compliance
[3C900B-FL(ST) only]
Reduces power consumption and enables Remote Wake Up.

Desktop Management Interface (DMI ) [3C900B-FL(ST) only] Lets you remotely gain PC resource and inventory information without costly desktop visits.

Optional Managed PC Boot Agent Enables Pre-OS installations, upgrades, and recovery. Also enables remote visits—even when the PC can't boot—to lower the cost of ownership.

Meets Wired for Management (WfM) specifications Supports WfM industry standards for remote management.
Easy Installation and Configuration
EtherCD™ CD-ROM
(PCI model only)
Includes an easy-to-use graphic user interface, point-and-click driver installation, driver utilities, enhanced post installation diagnostics, electronic user guide, and diagnostic and diskette creation utilities for easy installation and configuration.

Installation Wizard
(ISA models only)
Enables simpler troubleshooting and administration with Windows-based configuration and diagnostics utility.

Plug-and-Play for Windows 95 and 98 Provides quick and easy installation in popular operating systems.

Auto-installation software In NetWare, a single menu choice configures the NIC and installs drivers on non-plug-and-play PCs.