Star-Tek 299AT-1P Active Twinax Hub 7-Port RJ11 IBM AS/400 5250 Terminal

Star-Tek 299AT-1P Active Twinax Hub 7-Port RJ11 IBM AS/400 5250 Terminal

The Star-Tek 299AT-1P is a 7-port active twinaxial hub designed to extend and distribute IBM twinax network connections using standard RJ11 wiring. It serves as a wiring concentrator in IBM 5250 terminal networks, allowing multiple workstations or terminals to connect to a single twinax segment through convenient RJ11 modular jacks rather than traditional bare twinaxial cable. The front panel features a PORT indicator, LINE and SYNC status LEDs, and individual status LEDs for each of the seven ports (labeled 0–6).

Specifications & What's Included

• Model: Star-Tek 299AT-1P
• Type: Active Twinaxial Hub
• Number of Ports: 7 (RJ11 modular jacks, labeled 0–6)
• Connector Type: RJ11
• Interface: Twinaxial (Twinax)
• Front-panel indicators: PORT, LINE, SYNC status LEDs; individual per-port status LEDs
• Enclosure: Black metal chassis with integrated side mounting brackets
• Compatible with: IBM AS/400, System/36, System/38, and 5250-family terminals
• Unit only (no cables included)

Applications

Twinaxial networking was IBM's proprietary wiring standard used throughout the AS/400, System/36, and System/38 midrange computing era — primarily from the late 1970s through the 1990s. In these systems, up to seven 5250-type terminals (display stations and printers) share a single twinax segment daisy-chained from the host controller. Active hubs like the 299AT-1P replace the daisy-chain with a star-wiring topology, simplifying installation and troubleshooting by using standard RJ11 telephone-style cabling to each endpoint. This made structured wiring closet setups practical in offices and data centers running IBM midrange equipment. Today, Star-Tek 299AT-1P hubs remain in use wherever legacy AS/400 (IBM iSeries) infrastructure is still maintained, and are sought by shops keeping older IBM midrange systems operational.