Remember when there were no cell phones? Hint: It was 25 years ago this month that the first commercial mobile call was made from the U.S., ushering in the era of constant communication.

Fittingly enough, Bob Barnett, then-president of Ameritech Mobile Communications, rang up the great-grandson of telephone inventor Alexander Graham Bell in Germany. Barnett placed the call on a so-called brick phone (a Motorola DynaTAC 8000X that weighed a hefty two pounds, was 13 inches long, and could only be used for 30 minutes of conversation) from a Chrysler convertible in the parking lot of Chicago's Soldier Field, according to the Wireless Association, the industry's Washington, D.C.-based trade group. It cost nearly $4,000, according to the Chicago Sun Times.

The first actual cell phone had been invented a decade earlier by Motorola's then-director of research Martin Cooper, who made the first-ever call on a handheld mobile in April 1973 from a Manhattan street corner to his counterpart Joel Engel at rival Bell Labs in New Jersey. It took another 10 years to get federal regulatory approval for a commercial version, airwaves allocated and to develop the technology to switch frequencies between call locations, according to Motorola. 

Since that fateful day, cell phones have become "small enough to be confused with a suppository," to quote a recent review in Gizmodo of the Haier Black Pearl, and cost as little as $40 each month. 

Now text messaging is eclipsing voice communication on cell phones: Carriers reported more than 384 billion texts in the first six months of this year, compared with 295 billion calls. And cameras, the Internet and GPS are becoming ubiquitous on mobile phones.

At the same time, scientists and industry are embroiled in a controversy over whether the devices cause brain tumors. That worry escalated 15 years ago when a Florida man appeared on CNN's Larry King Live, claiming that cell phone use had given his wife brain cancer. In July, a Pittsburgh cancer center warned its employees to limit their conversations on mobile phones, and to keep them away from children altogether. The Wireless Association insists the phones are safe.

We'll have to stay tuned for the verdict on mobile health, but for now, the phones are seen as a necessity by much of the planet: There are 3.3 billion cell phones in use on Earth, with 2.6 million subscribers in the U.S., according to the association. The U.S. is still trying to catch up to countries such as South Korea, though, where high-speed, broadband phone networks are the norm.

(Motorola "brick phone" via Flickr/yum9me,