Shane Bauer and Josh Fattal, both 28, had staged a 17-day hunger strike after they stopped receiving letters.
The call home was only their third since their arrest nearly two years ago.
Fattal, Bauer and Bauer's fiancée Sarah Shourd were arrested along the Iraq-Iran border in 2009 and held on espionage charges, which they deny.
Shourd was allowed to return to the U.S. last year on bail. Iranian officials ordered her back to Tehran for the trial, and she has refused to do so.
Bauer's mother, Cindy Hickey of Pine City, Minn., said her son's phone call was about four minutes and that he sounded "OK."
"I was very glad to hear his voice," Hickey said. "We want him home."
The trial had been scheduled to resume on May 11, but the men weren't brought to court and no explanation was given to the families or their lawyer in Tehran. Hickey said her son "has no idea why he wasn't brought to court or what was going to happen next."
The phone calls were the first the families had received from Bauer and Fattal since Nov. 27, 2010.
The Associated Press contributed to this story.