‑ MORRISTOWN, NJ (AP)

About 30 ham radio operators gathered Sunday at the factory where Samuel F. B. Morse's telegraph was first publicly demonstrated to celebrate the 150th anniversary of the revolutionary technology.

Today is the anniversary of the day the telegraph sent the message, "Railroad cars just arrived, 345 passengers".

The ham radio operators sent a message around the world in Morse code and in voice to other hams to commemorate the occasion.

"Morse code is very important to ham operators," said Peter Glerm, one of the ham radio operators transmitting at Historic Speedwell, the 7.5‑acre estate where Morse tested the telegraph.

Although it has been largely replaced by voice and data transmission, "Sometimes there may be times when the only type of message you can use is one of Morse code," he said.

Those times include emergencies such as the Mexico City earthquake, when there is so much interference or the signals are so weak that Morse code is the only available form of communication.

The gathering of the ham radio operators was part of a year‑long series of events to mark the telegraph's contribution to technological progress, said Sarah Haskins, executive director of Historic Speedwell, now a museum.

The museum formed a corporation to coordinate activities this year and, along with the New Jersey Commission on Science and Technology, was a co‑sponsor of the weekend events, she said.

While Morse invented the telegraph, he was supported financially and technically by a Morristown family.

Alfred Vail, the son of a wealthy Morristown entrepreneur, was intrigued by a demonstration of Morse's telegraph and persuaded his father to invest $2000 in the invention.

Ham radio operators Sunday celebrated the anniversary by transmitting this message: "We are commemorating the 150th anniversary of the first public demonstration of the electromagnetic ...