Fifteen years after he patented caller ID technology, Brazilian inventor Nelio Jose Nicolai is no millionaire.

Quite the opposite: out of work since 1984, the co-inventor of the ubiquitous tool is still fighting to collect royalties.

"This revolutionized cellular telephony," Nicolai proudly told AFP of his BIMA technology, recalling the rapturous welcome it received in Canada and the United States.

In 1996, the inventor received an award from the World Intellectual Property Organization and a year later -- after a five-year wait -- he finally secured a patent in his homeland.

He then approached domestic mobile phone operators to claim his rights to royalties -- and ran into a wall.

"One of the companies told me: 'Go to court, maybe your great-grandchildren will collect something,'" the 72-year-old said. "So I decided to defend the rights of my great-grandchildren."

Over the years, BIMA was modified and named caller ID.

But, despite repeated efforts, Nicolai was unable to secure the rights to the new name, causing him to lose out on millions of dollars.

"The financial prejudice caused is shameful. It's a crime against the state, because it affects the equity of not only an individual but of a country," he fumed.

Home to 194 million people, Brazil has more than 250 million mobile phone lines in use and each operator charges a monthly average of $5 for caller ID service, according to Nicolai's lawyer Luis Felipe Belmonte.

Nicolai has filed lawsuits against leading cellular operators Claro, owned by Mexican telecom magnate Carlos Slim, as well as Vivo, owned by the Spanish group Telefonica.

Due to financial woes that almost left him homeless, he was forced to accept a settlement with Claro, which agreed to pay him only 0.25 percent of his request.

Details of the deal are being kept under wraps but the proceeds enabled Nicolai to buy a upscale house in Brasilia, as well as a new Mercedes sedan. Now he hopes to collect more from other lawsuits.

"To be Bill Gates or Steve Jobs in the United States, that's easy," Nicolai said in reference to the founders of Microsoft and Apple. "But I would like one of them to be an inventor in Brazil."

In Brazil, registering a patent costs up to $1,500 and the procedure takes an average of five years and eight months, compared with four years in the United States and five in Europe.

"The main problem is the wait," which makes it difficult to market ideas, conceded National Institute of Industrial Property president Jorge Avila, who each year receives around 35,000 patent applications.