NEW YORK ( TheStreet) -- AT&T ( T) shares slipped after the market close on Tuesday after the company missed Wall Street's first-quarter revenue estimate. The telecom giant reported sales of $31.4 billion, down 1.5% compared to the prior year's quarter. Analysts surveyed by Thomson Reuters were looking for revenue of $31.75 billion. The top-line miss pushed AT&T's shares down 2.31% to $38.10 in extended trading. Excluding items, AT&T earned 64 cents a share, up from 59 cents a share in the prior year's quarter and in line with Wall Street's forecast. The Apple ( AAPL) iPhone partner sold 6 million smartphones -- a first-quarter record. AT&T added 1.2 million postpaid smartphone subscribers during the quarter. The company said that 72% of its postpaid phone subscribers had smartphones, up from 61% in the year ago quarter. AT&T's total wireless revenue was $16.7 billion, an increase of 3.4% on the prior year's quarter. The Dallas-based firm posted a net increase of 291,000 total wireless subscribers during the quarter. "Our wireless network performance continues to be terrific," said Randall Stephenson, AT&T CEO, in a statement. "And that helped drive our best ever first quarter for smartphone sales, improved wireless churn and strong growth in mobile data revenues." Wireless postpaid churn was 1.04%, down from 1.1% in the year-ago quarter and from 1.19% in the fourth quarter of 2012. Within the wireless segment, mobile data revenue was up 21% compared to the same period last year. AT&T's wire-line revenue was $14.7 billion, down 1.8% compared with the same period last year. -- Written by James Rogers in New YorkFollow @jamesjrogers >To submit a news tip, send an email to: firstname.lastname@example.org.