By Reuters

AT&T, which took full control of No. 1 U.S. mobile carrier Cingular with its $86 billion purchase of BellSouth last month, will launch on Monday a campaign to mark the change.

"We did not enter that decision lightly," Wendy Clark, vice president of advertising at AT&T, said in an interview. "We came to understand that consumer customers and business customers alike are looking for a single provider. We heard it so consistently across the marketplace."

In its first stage, Cingular will share its orange logo of a bouncing jack with the AT&T globe logo on everything from television ads to sales uniforms and monthly bills.

AT&T 's name and logo will eventually replace Cingular in a process expected to take several months, with the exact timing determined as more customer feedback comes in, Clark said.

But with its long and complicated history, AT&T may face customer confusion over its name, marketing experts said. Also, Cingular built up a reputation among younger customers who may not easily associate with the AT&T brand.

At stake are AT&T 's efforts to promote its bundle of phone, Internet and video services against a growing number of rivals, including cable operators and Web providers.

One new ad will portray a familiar Cingular image--grain harvesters mowing a field to represent "bars" showing maximum cell phone reception. But in a new take, the harversters will change direction and mow the AT&T globe out of the stalks.

"It's a tough proposition," said Hayes Roth, chief marketing officer at brand agency Landor Associates. "Multiple brands within any company is expensive. Arguably they don't have much choice, they've made a stand now that they've invested back in the core brand."

Cingular spent nearly $1 billion on media advertising in the first nine months of 2006, up from about $920 million in the same period during 2005, according to the latest data from tracking firm TNS Media Intelligence.

For the remainder of their businesses, AT&T spent nearly $600 million on media ads in the nine-month period, while BellSouth spent just over $100 million, TNS said.

AT&T has said about 20 percent of operating cost savings in the BellSouth merger will come from lower advertising costs.

The new AT&T was formed in the merger of SBC Communications and AT&T in late 2005. Adding to the mix, in late 2004 Cingular bought AT&T Wireless, eradicating that brand for its poor reputation among customers.

"The good news is there is a difference between AT&T and AT&T Wireless," Clark said. "We have benefited significantly...by having 12 months under our belt as the new AT&T."