DSET Ships ezNumberPort 3.1

New Number-Porting Gateway Eliminates A Major Expense for Service Providers

Bridgewater, NJ - May 10, 2001 - (Nasdaq: DSET) - DSET Corporation today announced the availability of Version 3.1 of its ezNumberPort electronic-bonding gateway. The ezNumberPort gateway enables local number portability (LNP) by automating interconnection between competitive service providers and the eight regional Number Portability Administration Centers (NPACs) in the United States and Canada, which are managed by NeuStar, Inc.

LNP allows a customer to keep the same telephone number when switching from an incumbent carrier to a competitive local service provider. To accomplish this, both the incumbent carrier and the customer's new provider exchange data with one or more NPACs. For a competitive carrier, ezNumberPort helps to automate the process of activating local service for new customers at ported numbers by electronically interconnecting with the appropriate NPAC systems.

The benefits of deploying the ezNumberPort gateway also include providing a very cost-effective alternative to the generic NPAC interface for downloading reports about pending number ports, which could be tens of thousands annually for a successful competitive carrier. Regularly downloading such reports allows a service provider to manage its operations much more efficiently and economically.

"ezNumberPort has saved substantial amounts of money for providers," said Michael McLaughlin, DSET's director of product management. "Last year, one of the largest competitive service providers in the U.S. spent close to a million dollars to download LNP reports from NPACs via the basic low-tech interface (LTI) available through NeuStar. This carrier, which had already deployed other DSET gateways, recently installed ezNumberPort and expects to dramatically cut most of the costs associated with LNP."

"With this level of savings, along with other operational improvements possible through ezNumberPort automation, a service provider's return on investment could be a matter of months," added Jimmy Jobe, DSET's senior vice president of product development.

Access to ezNumberPort capabilities has been improved by upgrading the graphical user interface with several performance enhancements, including Java 1.2 support. ezNumberPort 3.1 conforms to the current version (3.0) of the NPAC SMS Interoperable Interface Specification issued by the North American Numbering Council (NANC). It is compatible with NANC 2.0 as well, allowing simultaneous interconnection with NPACs using either Version 2.0 or Version 3.0.

"Since its introduction, our ezNumberPort gateway has become an increasingly capable and flexible solution," said DSET product manager Nathan Bond. "ezNumberPort 3.1 can be used as a stand-alone solution or it can integrated with a provider's order management system to facilitate flow-through processing. It also supports national number pooling, which will help to extend the life of the North American Numbering Plan for decades.

"Of course, the exceptional data query capability that the new version of ezNumberPort offers is a key contributor to the various savings that providers can realize with this product. Being able to automatically access the LNP information a provider needs from any NPAC, when it's needed, and without any 'black-out' periods can save hundreds of thousands of dollars each year."

About DSET:

DSET is a leading supplier of software known as electronic-bonding gateways that enable competitive service providers in the telecommunications industry to implement an automated Trading Partner Network (TPN). A TPN plays a critical role in lowering the cost of acquiring customers, reducing the amount of time required to turn on services for new customers, and minimizing the time required to resolve service outages to ensure higher customer satisfaction and less customer turnover. DSET provides the installation, training, interoperability-testing, and maintenance services needed to put TPNs into production and maintain efficient operation. DSET is headquartered in Bridgewater, New Jersey, and the company's Web site can be viewed at www.dset.com.

Statements regarding financial matters contained in this press release, other than historical facts, are forward-looking. Since all statements about DSET's plans, estimates, and expectations are based on current projections that involve risks and uncertainties, and are subject to change at any time, the company's actual results may differ materially from expected results. Investors should consider these risks and uncertainties, which are discussed in documents filed by DSET with the Securities and Exchange Commission. These documents identify important factors that could cause the actual results to differ materially from those contained in the projections or forward-looking statements. DSET expressly disclaims any obligation to update any forward-looking statements.

x x x

DSET Contacts:

Media Relations: Dean Maskevich, Marketing Communications, 908-526-7500 Ext. 1366,
e-mail: dmaskevi@dset.com

Investor Relations: John P. Murphy, Westfield Investor Relations, 908-233-1558, e-mail: westfieldir@worldnet.att.net

DSET and the DSET logo are registered trademarks of DSET Corporation.

All other trademarks are the property of their respective owners.