Concentric Signs Letter of Understanding With Tachyon to Use Two-Way Satellite Solution.

Business Editors/High-Tech Writers

LAS VEGAS--(BUSINESS WIRE)--May 10, 2000

Concentric Will Use Tachyon's Satellite to Deliver

High-Speed Internet Connectivity to Business Customers

Tachyon, Inc. today announced it has signed a Letter of Understanding (LOU) with Concentric Network Corp. (Nasdaq: CNCX), a leading provider of e-business solutions for growing companies. The letter calls for both companies to execute an agreement within 45 days wherein Concentric will partner with Tachyon to offer high-speed Internet access over Tachyon's satellite systems.

"Our partnership with Tachyon will allow Concentric to offer truly ubiquitous coverage to our business customers, and will perfectly complement our existing suite of access products," said Mark Fisher, senior vice president of marketing for Concentric. "Furthermore, Tachyon boasts quick installation times, a user-friendly support interface, and an excellent engineering and support organization, which are critical service elements for our customers."

"More than two years ago during our development phase, Tachyon looked to Concentric for help in shaping our technology and business concepts," said Dr. John E. Koehler, founder and president of Tachyon. "They were a supportive and thorough trial participant. It is very satisfying to see this relationship come to fruition."

Tachyon is the first and only company to bring to market two-way, high-performance, satellite-delivered Internet service. The LOU follows a busy first and second quarter rollout for Tachyon's last mile satellite delivered local loop(TM) service. Nine U.S. Internet Service Providers (ISPs) and one European ISP have become Tachyon partners since the San Diego-based company brought its Tachyon.net(TM) service to market in late January.

Tachyon offers three tiers of service with data rates of 300Kbps, 800Kpbs and 2Mbps and guarantees installation within 10 business days of an order. Tachyon uses the capacity of already in orbit geostationary satellites. The technology took two-and a-half years of engineering development and resulted in the filing of 20 patents.

Tachyon has designed its system and service to extend to an end-user's location, the same kind of service guarantees and network monitoring that top-tier service provider such as Concentric offer on their own networks. These include 24/7 active monitoring, guaranteed first mile service level agreements and consistency with TCP/IP protocols at each end. Tachyon's world headquarters are in San Diego, with Mesoamerican headquarters in Mexico City and European headquarters in Amsterdam. For more information, visit the company's web-site at www.tachyon.net.