DSET and Mercator® Partner for Faster Deployment of Telecommunications
E-Commerce Solutions

Strategic Alliance Improves B2B Commerce Among
Competitive and Incumbent Local Exchange Carriers

BRIDGEWATER, NJ and WILTON, Conn. - February 23, 2000 - DSET Corporation (NASDAQ:DSET), a leading supplier of business-to-business e-commerce solutions for the telecom industry, and Mercator® Software (NASDAQ:MCTR), the e-business transformation company, today announced a partnership and reseller agreement that will streamline the deployment of key B2B interfaces between competitive local exchange carriers (CLECs) and incumbent local exchange carriers (ILECs). Under the terms of the multi-year agreement, DSET is licensed to embed Mercator Enterprise Broker in the DSET gateway that electronically interconnects CLECs with ILEC trading partners and automates the processing of phone-service orders for new CLEC customers.

"Our commitment to Mercator's e-business integration software as both a 'Mercator Telecommunications Industry Partner' and a 'Mercator M-Powered ISV Partner' will solidify the position of our ordering gateway as a powerful B2B e-commerce solution for the industry," said Paul Smith, DSET's senior vice president of strategic planning and product management. "This agreement underscores our confidence in Mercator as a leading B2B integration solution that can stand up to the challenges ILECs present to their CLEC trading partners. Of equal importance, the multi-year agreement signals DSET's confidence in the market for interconnecting competitive and incumbent carriers. Embedding the capabilities of Mercator Enterprise Broker in our gateways helps ensure that we rapidly and accurately meet and exceed the changing ILEC interface requirements."

The Mercator e-business transformation software has been an integral component of DSET's ordering gateway since its introduction in late 1998. However, DSET has made a significant new commitment to Mercator in anticipation of continued strong demand for the DSET gateways.

"Our strategic relationship with DSET validates Mercator's position as the preferred e-business integration offering for the telecommunications market," said Dave Power, vice president of marketing, Mercator. "We are committed to a strong partnership with DSET to provide rich transformation capabilities in the DSET gateway that should expand the opportunities for both companies to better serve our telecommunications customers. We expect the ease of deployment and maintenance of the connection between CLEC-ILEC trading partners to result in increased value for DSET's customers and expanded opportunities for Mercator."

DSET solutions make turning on service for new CLEC customers faster and more cost-effective, beginning with the company's products for automatically generating sales quotes. DSET solutions automate the process of ordering local loops and high-capacity circuits, and provide support for number portability, 911 emergency service, calling card, and caller ID services. DSET products also ensure that CLEC customers are served by their preferred long-distance carriers and that service problems are resolved quickly and efficiently.

About Mercator Software
Mercator is the leading provider of e-business transformation software. The company's products dramatically simplify customer migration to e-business across every industry, providing unprecedented levels of automation for the most difficult e-business integration tasks. Mercator integration broker products address customer requirements for business-to-business (B2B), application-to-application (A2A) and consumer-to-business (C2B) integration in every industry. More than 5,000 customers use Mercator products to accelerate their transformation to e-business and over 100 partners embed or resell the company's technology to enhance their product or service offerings. Additional information about Mercator can be found on the Internet at www.mercator.com.

Mercator Software is the new trade name of TSI International Software, Ltd., headquartered in Wilton, Connecticut. The company will seek stockholder approval to formally change its name at an upcoming stockholders meeting.

Legal Notice Regarding Forward-Looking Statements: Statements in this press release that are not purely historical are forward-looking statements, including statements regarding TSI International Software Ltd.'s (the Company) beliefs, expectations, hopes or intentions regarding the future. Forward-looking statements in this release include, but are not limited to, statements regarding the growth of the enterprise application market, the demand for the Company's application integration solutions and the speed of deployment of new products, including combined Mercator E-business Integration Broker products. It is important to note that actual outcomes and the Company's actual results could differ materially from those in such forward-looking statements. Factors that could cause actual results to differ materially include risks and uncertainties such as changes in demand for application integration or e-business integration software and the Company's Mercator E-business Integration Broker suite of products in particular, the ability of the Company to expand its international operations, the ability of the Company to manage expanded global operations, the ability of the Company to continue to add resellers and other distribution channels, and the success of third parties in utilizing and marketing the Company's products, or seasonality in operating results. Readers should also refer to the risk disclosures outlined in the Company's reports filed with the Securities and Exchange Commission. All forward-looking statements and reasons why results might differ included in this release are made as of the date hereof, based on information available to the Company as of the date hereof, and the Company assumes no obligation to update any such forward-looking statement or reason why results might differ.

About DSET
DSET Corporation is a leading provider of business-to-business e-commerce solutions for the global telecommunications marketplace. The DSET suite of electronic-bonding gateways is designed to interconnect the operations support systems (OSSs) of service providers that must exchange information and share network capabilities with trading partners to provision and maintain a growing range of services for customers in the competitive telecom market. DSET's local number portability solutions play a key role in enabling business and residential customers to change service providers without changing their local phone numbers. 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.

###

DSET and the DSET logo are registered trademarks of DSET Corporation. Mercator is a registered trademark of TSI International Software Ltd., d/b/a/ Mercator Software. "the e-business transformation company" is a trademark of TSI International Software Ltd., d/b/a Mercator Software.

DSET Contacts:
Media Relations: Kathy Claxton, Corporate Marketing Communications Manager, 908-526-7500 Ext. 1280

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

Mercator Contacts:
Media Relations: Ted Weismann or Amy Pavel, Lois Paul & Partners, 781-238-5700

Public and Investor Relations: Cindi Brockhoff, Director, Market Relations, 203-761-8600