Certified WiMAX equipment, which was expected to be available to wireless service providers in the first half of this year, will be at least six months late, at least one industry source has confirmed.

Dean Chang, director of marketing for wireless broadband equipment vendor Aperto Networks, confirmed the delay and said there were two reasons f or it.

"One of the biggest things is that there are companies making semiconductors for the consumer premises equipment (CPE) and some of their schedules didn't come to fruition," Chang said in an interview Tuesday. "The other reason is that it took longer to set up the lab and the team. Our team was very optimistically aggressive on the dates."

Chang chairs the service provider working group for the WiMAX Forum and also is publicity chair for the 802.16 working group.

Many Forum members had said that they expected public interoperability testing, sometimes called "plugfest," to start this month with fully certified equipment to be available from vendors by mid-year. Now, Chang said that conformance testing, which matches specific equipment's ability to conform to so-called system profiles dictated by the standard, should begin in June.

"If things go well then, it'll be another month or so for the plugfest to occur," Chang said. He added that, if that schedule comes to pass, fully certified WiMAX equipment should appear around the end of the year, six months or so later than expected.

Chang said he doubted that the delay will hurt WiMAX equipment vendors who already are selling pre-standard equipment.

"Sales by most suppliers are going through the roof," Chang said. "We've (Aperto) grown substantially because there is a view on the part of a lot of customers that there will be a standard."

After certified equipment appears, vendors will update customers, who include wireless Internet service providers (WISPs) and larger telecom operators. But, in the meantime, some operators are offering "pre-WiMAX" service and others will buy the equipment in order to let their end customers, typically enterprises, run tests.

"You would think that, in a mass market, customers would wait for standard products to come out," Chang said. "It's odd, but this market is going the other way."