Motorola Vanguard 311 ISDN Router Plus U-Intf PC 68237 128Kbps BRI Desktop

Motorola Vanguard 311 ISDN Router Plus U-Intf PC 68237 128Kbps BRI Desktop

The Motorola Vanguard 311 is a desktop BRI ISDN router designed for small office and remote site connectivity over Basic Rate ISDN lines using the U-Interface standard. It integrates an ISDN terminal adapter and a LAN bridge/router in a single compact desktop unit, allowing Ethernet-connected devices to communicate over ISDN bearer channels. The unit is identified on its bottom label as "ISDN Router Plus U-Intf" with product code PC 68237, and carries an Industry Canada certification (109 7138 R), indicating it was sold and approved for use in Canada.

Specifications & What's Included

• Make/Brand: Motorola
• Model: Vanguard 311
• Product Code (PC): 68237
• Type: ISDN BRI Router / Bridge — U-Interface
• WAN Interface: ISDN-U (BRI, 2B+D)
• LAN Port 1: 10Base-T (RJ-45)
• LAN Port 2: 10Base-2 (BNC coaxial)
• Serial/Console Port: CTP (DB-9)
• Power Input: 100–250V AC, 50/60Hz, 0.7–0.3A (universal)
• Power Connector: DIN/PS2-style circular jack (rear panel)
• Form Factor: Desktop
• Front Panel LEDs: STS, TST, LAN, TLD, B1, B2
• Certification: Industry Canada 109 7138 R
• Included: Unit only — no power cord

Applications

The Motorola Vanguard 311 belongs to the Vanguard 300 series of ISDN access routers, a product line Motorola developed in the mid-to-late 1990s for branch office and SOHO WAN connectivity. BRI ISDN (Basic Rate Interface) provides two 64 Kbps B-channels and one 16 Kbps D-channel over a standard two-wire telephone loop; the Vanguard 311's U-Interface connection means it connects directly to the ISDN U-loop from the telco, without requiring a separate NT1 device. The dual Ethernet ports — one 10Base-T and one 10Base-2 — allowed connection to both twisted-pair and coaxial Ethernet segments, which was common in office networks of that era. Units like this were used to provide cost-effective WAN links for remote offices connecting back to a central site, replacing or supplementing dial-up modem access with faster, more reliable ISDN circuits. While ISDN has largely been superseded by broadband, DSL, and fiber in most markets, Vanguard 311 units are still sought by collectors of 1990s networking equipment, legacy network labs, and anyone maintaining or studying period-accurate network infrastructure.