Carrier One Selects TNS to Route VoIP Calls; Voice over Internet Protocol Wholesaler to Use TNS' Least Cost Routing Platform.

RESTON, Va. -- Transaction Network Services, Inc. (NYSE: TNS), a leading network and data communications provider for transaction-oriented applications, announced today that Carrier One, a Voice over Internet Protocol (VoIP) reseller offering high capacity enhanced telecommunications services, has selected TNS to provide VoIP call routing and validation services via TNS' Least Cost Routing (LCR) SS7 network platform.

TNS' LCR solution is ideal for Carrier One as they only need an Operating Company Number (OCN) to assist them in routing calls, rather than a full-blown Line Information Database (LIDB) query. In addition, the TNS validation solution provides a simple internet interface and allows Carrier One the ability to pass database information through to its customers and affiliates. Carrier One expects to send between one to five million LCR queries per month over the TNS network.

"TNS will allow us to better serve our customers. In fact, TNS was the only SS7 provider that actually has a usable and simple interface for querying LIDB today, as opposed to being six months away," explains Justin Hannah, president of Carrier One. "By allowing us to pass database information through to our customers, working with TNS has given us a competitive edge with our wholesale VoIP customers, allowing them to effectively least cost route and bill in real time actual rates based on the terminating carrier."

"We are excited to work with such an innovative company as Carrier One," explains Barry Toser, senior vice president and general manager, Telecommunication Services Division of TNS. "Our relationship with Carrier One is another example of TNS' commitment to delivering the SS7 and VoIP services that the telecommunications industry is looking for."

About Transaction Network Services, Inc.

Transaction Network Services (TNS) is one of the leading providers of business-critical, cost-effective data communications services for transaction-oriented applications. TNS provides rapid, reliable and secure transaction delivery across multiple vertical markets and trading communities.

Since its inception in 1990, TNS has designed and implemented multiple data networks, each designed specifically for the transport of transaction-oriented data. TNS' networks support a variety of widely accepted communications protocols and are designed to be scalable and accessible by multiple methods. TNS' network technologies have been deployed in the United States and internationally, and TNS' networks have become preferred networks servicing the trading community, wireless and wireline carriers, and the card processing and dial-up automated teller machine markets. For further information about TNS' transaction solutions, please refer to www.tnsi.com.

Forward-Looking Statements

The statements and information contained in this press release that are not descriptions of historical fact may contain forward-looking statements. Forward-looking statements involve a number of risks, uncertainties or other factors beyond TNS' control, which could cause actual results to differ materially from historical results or performance and from any opinions or statements expressed with respect to future periods. TNS disclaims any obligation to update or correct any forward-looking statements made herein due to the occurrence of events after the issuance of this press release.