SANTA CLARA – When Alex Smith reached the NFL in 2005, he figured the world's most powerful sports league would use the most cutting-edge technology and top-of-the line equipment.

Instead, he looked inside his helmet to find a few AAA batteries and a balky radio device that would become a tremendous headache for Smith and the 49ers organization in recent years.

This season, however, the NFL is undergoing a tech upgrade, tossing out the old analog system that offensive coordinators used to relay plays to their quarterbacks and implementing one that runs on digital technology.

The league successfully tested the new system last preseason and in the Pro Bowl, and it will be used Sunday in the Hall of Fame game in Canton, Ohio. The 49ers tried it out during Friday's practice, and Smith gave it a conditional thumbs up.

"It's clearer off the bat, and it comes in better," Smith said. "But the last couple of years, it seemed like we never had any problems on the practice field. It's not until you get to the stadium that for some reason it doesn't seem to work as well."

The issue was particularly acute two years ago when Jimmy Raye was the offensive coordinator. The team's inability to get plays into Smith on time was the subject of a scathing Yahoo! Sports story that painted Raye as overmatched by the speed of the game and helped accelerate his ouster.

Last year, the 49ers weren't as flummoxed by the radio relay system, but problems persisted. Smith said the connection often would cut out – sometimes in the middle of a play call – causing the team to use hand signals or forcing Smith to improvise.

The issue usually cropped up when the 49ers were on the road. But it happened at Candlestick Park, too.

Said offensive coordinator Greg Roman: "There was one time when I was doing it, and it happened to be on the same frequency as an airline in a certain city. And it was a critical situation in the game, and all you hear is Southwest pilots talking."

So did he hear whether the flight landed safely?

"No," Roman said. "Never checked to see if it got in."

Crabtree watch – Wide receiver Michael Crabtree (calf) missed his sixth straight practice, but coach Jim Harbaugh didn't seem too concerned about the lost time.

"He came in in such great shape," Harbaugh said. "I don't think this is going to be a major bump in the road. I think it's a minor one."

For the last three days, Crabtree has been rehabilitating on a side field with the 49ers' strength and conditioning coach, a routine that includes sprinting nearly the length of a football field. That's typically the last step an injured player takes before returning to the field.

Et cetera – Left guard Mike Iupati was excused from practice for the birth of his first child. Leonard Davis filled in with the starting group and played well.

• Fourth-round draft pick Joe Looney participated in his first practice after recovering from a foot injury he suffered in January. Looney played right guard with the second-team offense.

• For the second day in a row, the defense dominated the offense. The practice ended when cornerback Tarell Brown tipped one of Smith's passes to safety Dashon Goldson for an interception.

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