Isis, the mobile-wallet joint venture formed by AT&T, Verizon Wireless and T-Mobile USA, launched its test today in Salt Lake City and Austin, Texas.

The venture's mobile-pay product allows consumers to make contactless payments at the point of sale by using a phone with an embedded near-field communication chip. Isis says it currently works with nine handsets, with another 11 set to support it by yearend.

"Today's launch of the Isis Mobile Wallet is a significant achievement in terms of enabling consumer adoption of mobile payments," said Suzan Kereere, senior vice president and general manager for American Express' global network business, in a press release.

American Express, JPMorgan Chase and Capital One Financial earlier signed on as issuer partners for Isis. These companies are granted a ‘widget' within the Isis wallet they can brand for their own customers. Amex also offers its own digital wallet, called Serve.

"American Express' first priority as a network is to provide choice and flexibility for all industry participants as we work together to influence the speed and growth of mobile NFC payments in the U.S.," Kereere said.

Consumers can also fund mobile payments with an Isis Cash card.

Isis did not name the handset models that work with its mobile wallet. Consumers interested in using Isis must go to a carrier's retail store in one of the test cities to get the proper phone.

Isis' nine phones puts it in line with, or slightly ahead of, Google Wallet, another NFC-based mobile payment system. As of last month, Google's product worked with six Android smartphones, as well as the company's Nexus 7 tablet.

Google also has a partnership in place at one of the Isis test locations, Salt Lake City. Google said last month it is working with Utah's Associated Food Stores to accept mobile Google Wallet payments early next year.

Isis earlier promised to launch by the end of the summer. Last week it confirmed its launch date moved to Oct. 22.