CHOICE ONE ACHIEVES ELECTRONIC BONDING SOLUTION WITH VERIZON-SOUTH
Automated Exchange of Information to Enhance Choice One's Provisioning Speed and Accuracy

Rochester, New York - September 13, 2000 -- Choice One Communications (Nasdaq: CWON), an Integrated Communications Provider offering facilities-based voice and data telecommunications services to small and medium-sized businesses, announced today that they have achieved full voice and data electronic bonding with Verizon-South (formerly Bell Atlantic) for provisioning DSL circuits.

Through DSET's (Nasdaq:DSET) ezLocal gateway, Choice One is now able to automate the exchange of complex local service request (LSR) data between its provisioning center and Verizon-South, the incumbent exchange carrier serving Choice One's Pennsylvania markets. Choice One previously had achieved an electronic bonding solution with the carrier's north region for voice and data circuit provisioning. This application greatly enhances Choice One's capability to now order all the facilities needed to provision service efficiently and cost-effectively throughout the entire Verizon footprint.

According to Kevin Dickens, chief operating officer of Choice One, "The completion of a full electronic bonding solution is a major accomplishment for Choice One and an integral component to providing increased speed to our order provisioning process. This equates to improved client service across the board. We are now able to provision lines in under twelve hours with a seamless interface to the incumbent carrier."

Dickens added, "In addition to reducing the time required to effectively process orders, electronic bonding enables us to ensure greater accuracy by reducing the amount of data entry keying, and eliminating redundancy. We no longer need to input data into multiple systems and this ultimately enhances our efficiency and accuracy while giving us a tremendous competitive advantage in the marketplace."

About Choice One Communications

Headquartered in Rochester, New York, Choice One Communications, Inc. (Nasdaq: CWON) is a leading integrated communications services provider offering voice and data services including Internet and DSL solutions, and web hosting and design, primarily to small and medium-sized businesses in second and third-tier markets.

Choice One currently provides or has announced plans to deploy services in twelve states throughout the Northeast and Midwest, U.S. On August 1, Choice One completed its merger with US Xchange, a facilities-based CLEC headquartered in Grand Rapids, Michigan. On a pro forma basis, the combined companies reported annualized second quarter revenue exceeding $84 million and had 1,150 total colleagues at June 30, 2000.

For further information about Choice One, visit our web site at www.choiceonecom.com or contact us at 1-888-832-5800.

About DSET

DSET Corporation (Nasdaq: DSET) is a leading provider of business-to-business e-commerce connectivity 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.

Forward-Looking Statements

Certain statements contained in this press release constitute "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995, and the companies intend that such forward-looking statements be subject to the safe harbors created thereby. The words "believes", "expects", "estimates", "anticipates", "will be" and "plans" and similar words or
expressions identify forward-looking statements made by or on behalf of the company. These forward-looking statements are subject to many uncertainties and factors that may cause the actual results of the company to be materially different from any future results expressed or
implied by such forward-looking statements. Examples of such uncertainties and factors include, but are not limited to, availability of financing and regulatory approvals, the number of potential customers in a target market, the existence of strategic alliances or relationships, technological, regulatory or other developments in the company's business, changes in the competitive climate in which the company operates and the emergence of future opportunities, all of which could cause actual results and experiences to differ materially from anticipated results and expectations expressed in the forward-looking statements contained herein. These and other applicable risks are summarized under the caption "Risk Factors" and elsewhere in the companies' Registration Statement on Form S-1, Registration No. 333-91321, filed with the Securities and Exchange Commission and declared effective on February 16, 2000.

Choice One Contact:
Ythan Lax Director, Corporate Communications (716) 530-2944 ylax@choiceonecom.com