On AT&T Inc.'s Web site, buyers who supply New York City ZIP codes were told on Monday morning to "Please shop for another phone."
AT&T has acknowledged that its data network is overburdened with iPhone users in New York and San Francisco, sparking online speculation that the sales suspension is a means of managing traffic.
However, because the phones are still available in New York retail stores and from Apple Inc.'s Web site, the ban could instead be a way to curb fraudsters who buy phones and sell them on eBay, reneging on the service contracts.
