Everybody's doing it. Mobile payments is one of the most interesting market segments to watch these days because there's so much activity and so much uncertainty. Each month appears to bring a new initiative. This month it's Google Wallet, next month it could be Apple or someone else. 

The carrier initiative ISIS, which is backed in part by AT&T, is largely doomed to fail in my view. That's because the carriers have to rely substantially on third parties to make it work and because they're simply not "entrepreneurial" enough. I don't mean to be so dismissive but this is my belief about the outlook for the effort.

However, AT&T is involved in another mobile payments that competes with Square. It's called Appriva. I just learned about it is week, although it has been around since last year.

At some point in Q3 last year AT&T quietly introduced the program: a mobile point of sale solution for businesses. The company hasn't done much (from what I can tell) to promote the service. As a result it has been largely overshadowed by other mobile payments initiatives.

It appears to be directed at small merchants though not exclusively. To enroll merchants need an AT&T phone (any smartphone apparently) the Appriva software/app and a merchant account. Appriva costs $14.95 for the regular service and $19.95 per month for AprivaPay Professional. It's not immediately clear what the additional benefits are from the "professional" account vs the regular service. 

Neither Square nor Intuit's GoPayment require a merchant account, which is a big advantage for the smallest businesses. Square has no monthly fees, beyond transaction charges, and GoPayment requires a $12.95 monthly charge for higher volume merchants. GoPayment has the advantage of integration with Intuit's other SMB software.

There are obviously many other companies in the mobile payments sector (including the lesser-known Square competitor ROAM). Any or all of them that have any traction and/or technology will be snapped up by larger firms and incumbents in the payment processing ecosystem. 

I think it's quite unlikely, given these simpler competitors and the lack of promotion, that AT&T's Appriva will find much adoption among small businesses. I could be wrong however.