Centillium Communications, Inc.

Christian Bateman
E&E; Public Relations
408-241-7449
[email protected] Patrick Murphy
Marconi Corporation plc
+44 115 906 4151
[email protected]

MARCONI SELECTS CENTILLIUM’S MAXIMUS ADSL2/2+/2++ CHIPSET FOR NEXT-GENERATION DSLAM PLATFORM

Centillium and Marconi team in offering next-generation services to carriers

HANNOVER, CeBit 2004, March 18, 2004 - Marconi Corporation plc (London: MONI and NASDAQ: MRCIY) and Centillium Communications, Inc. (NASDAQ: CTLM) today announced that Marconi has selected Centillium’s Maximus™ 12-port ADSL2/2+/2++ chipset for deployment in its Access Hub MSAN platform. The addition of Maximus enables network operators to deliver up to 50 Megabits per second (Mbps) of downstream bandwidth, 3 Mbps of upstream bandwidth and reach customers at distances up to 6,000 meters from the central office while maintaining full backward compatibility with over 65 million deployed ADSL modems.

Tony Shakib, Vice President and General Manager of Access and Network Business Units at Centillium Communications added, “We are excited to work with Marconi in deploying the latest ADSL2/2+/2++ technologies. Centillium has been on the forefront of ADSL2/2+/2++ technology development, and this alliance with Marconi represents a significant accomplishment for Centillium in one of our key target markets – Europe.”

Marconi’s Access Hub Platform
Marconi’s Access Hub, whose success was heralded recently by the signing of major contracts with British Telecom, Telecom Italia and a major service provider in Asia, confirms the benefits of going beyond basic DSLAM platforms by offering a true Multi-Service Access Node, supporting NGN-capable POTS/ISDN alongside ADSL2 and VDSL interfaces. With the introduction of a 60-channel ADSL2/2+/2++ card, the Access Hub reigns as the next-generation DSLAM with one of the industry’s highest port density nodes along with the ability to also act as a wireless and fiber aggregation point, supporting a wide range of distributed DSL topologies with its 25 different interface speeds.

With the introduction of the 60-channel xDSL line card (also available in the 48-channel sub-equipped version), the Access Hub now supports up to 1,200 xDSL lines in a single shelf, i.e. 2,400 per single 7-foot-rack. Such a density is made possible thanks to the advanced power management capability embedded in the Access Hub, yielding as low as 0.7 Watt/line.

“Always at the forefront of DSL technology and after launching recently its VDSL/POTS combo card, Marconi has selected Centillium for the impressive performances of the Maximus chipset in the field of ADSL2/ADSL2+ and READSL and has built into the Access Hub the upgrade capability to up to 50 Mbps downstream with ADSL2++ technology, making it a unique solution on the market,” said Devid Gubiani, Director, Product Line Management for Access Hub at Marconi Corporation plc.

Centillium’s Maximus Chipset
Centillium has shipped over three million Central Office (CO) ports based on the Maximus chipset, capable of supporting the latest ADSL2/2+, ADSL2++, READSL and line diagnostics features on a single platform. Each port can be individually configured to support various features. Maximus is a technology leader as the proven next generation ADSL solution in the market today, supporting the latest ADSL ITU-T G.992.3/G.992.5 standards. These features, coupled with the device’s high-level of integration and low-power consumption, make it an industry-leading DSL solution.

Further to the ADSL2/2+/2++ enhancements, Marconi and Centillium are announcing a strategic initiative for the development of Next Generation VDSL2 solutions. Built around Centillium’s next generation DSL chipset, this joint cooperation is intended to place Marconi’s Access Hub platform at the forefront of the emerging Fiber-to-the-Node (FTTN)/Fiber-to-the-Building (FTTB) market. This short-range Ethernet in the First Mile (EFM) extension would enhance Marconi’s Access Hub platform, with feature flexibility ranging from ADSL to VDSL2 and should create a compelling approach for the delivery of very high bandwidth to the user.

About Marconi Corporation plc
Marconi Corporation plc is a global telecommunications equipment and solutions company headquartered in London. The Company’s core business is the provision of innovative and reliable optical networks, broadband routing and switching and broadband access technologies and services. The Company’s aim is to help fixed and mobile telecommunications operators worldwide reduce costs and increase revenues.

The Company’s customer base includes many of the world’s largest telecommunications operators. The company is listed on the London Stock Exchange under the symbol MONI and on NASDAQ under the ticker MRCIY. Additional information about Marconi Corporation can be found at www.marconi.com.

About Centillium Communications
Centillium Communications, Inc. combines technical innovation and customer commitment to make broadband communications - in business and at home - a practical reality. The company designs and markets communications chipsets for Digital Subscriber Line (DSL) central office and customer premises equipment and for carrier- and enterprise-class Voice over Packet (VoP) gateways and switches. The Centillium Communications headquarters are located at 47211 Lakeview Blvd., Fremont, CA 94538. Additional information is available at www.centillium.com.

Forward Looking Statements
Except for historical information contained in this press release, the foregoing contains forward-looking statements that involve risks and uncertainties. Actual results may differ materially from those indicated by such forward-looking statements based on a variety of risks and uncertainties, including the risks and uncertainties relating to actual quantities and timing of any orders received under any contract and the successful development and market acceptance of Centillium's new products. The company assumes no obligation to update these forward-looking statements to reflect events or circumstances after the date hereof. Information about potential factors that could affect Centillium's financial results is included in Centillium's Annual Report on Form 10-K and most recent Quarterly Report on Form 10-Q, which can be viewed at the Securities and Exchange Commission’s website at www.sec.gov.

Centillium Communications and the Centillium logo are trademarks of Centillium Communications.