Adtran today reported a return to healthy spending among major U.S. carriers in the first quarter despite earlier predictions of a lingering pause in their purchasing.

In what is typically a slow season, the equipment vendor’s revenue was flat sequentially and up 2% from a year earlier to more than $110 million in the first quarter, beating both its own predictions (of between $102 million and $108 million) and the consensus of Wall Street analysts ($106 million). In a note issued today, UBS Investment Research called the results “solid.”

Adtran noted particular growth in broadband access revenue, which rose 33% sequentially to more than $18 million in the quarter, a 14% decrease from a year earlier.

Revenue from HDSL gear, up only slightly sequentially, was up nearly 23% from a year earlier to nearly $44 million, which one analyst on today’s conference call deemed “a pretty nice rebound.” A single customer (perhaps AT&T) that had slowed its HDSL purchases in the last two quarters of last year (perhaps due to its merger with BellSouth) resumed its traditional spending patterns, Adtran’s chief executive officer Tom Stanton said. But he didn’t know if the return to normalcy would continue. “If they lower their inventory level and learn how to manage the business at that level, you won’t see a snap-back,” Stanton said.

Revenue from optical gear was down slightly sequentially to $8.6 million in the quarter, with new contract wins from major carriers offsetting typical seasonality.

After lowering revenue expectations three times last year, Adtran predicted revenue growth in 2007 and sequential growth in quarterly revenue consistent with that seen in recent years.

Adtran’s biggest customers in the first quarter were AT&T (which contributed 29% of its quarterly revenue--only 4% of which came from the former BellSouth), Verizon Communications (which contributed 12%) and Embarq (which contributed 11%).

Revenue from Adtran’s Total Access 5000, unveiled a year ago, was insignificant in the first quarter. But interest in it, especially among major carriers, is giving the company cause for increased optimism. Long-term, Adtran’s newest products have the potential to double the size of the company, Stanton said, but at the moment, the pace of their growth is hard to predict.

“The success we’ve seen in the 5000, this early on in its launch, is surprising,” Stanton said. “Its acceptance seems to be growing faster than any product I can remember delivering.”

Adtran claimed to be engaged with all of the top-tier U.S. carriers for a mix of applications, including fiber-to-the-node (using the 5000 in combination with its 1100 outside plant DSLAMs), Ethernet-over-copper and others. Those activities likely wouldn’t yield revenue until next year, Stanton said. “We could probably see something toward the tail end of this year, but I’d be very surprised.”