It's the kind of jewelry you would expect to find on Captain Marvel or Buck

Rogers in the 25th Century. But today it has your name on it.

Dallas Semiconductor and Minneapolis-based Jostens Inc. have introduced a new digital decoder ring with an embedded memory chip that can access personal computers and control entry to offices, laboratories, bank vaults or warehouses for high-tech products. It can also buy your morning cup of coffee.The memory chip in the ring features a built-in read/write function, as well as a transmitter/receiver capable of receiving and sending data. The chip is formatted in data files like a floppy disk.

"The decoder ring brings jewelry into the information age. This product has tremendous communication and security applications," said Bob Burhmaster, president of Jostens Recognition Division.

"Rings have always provided a mark of distinction; now they can communicate directly with your personal computer to positively identify you as its owner," said Michael Bolan, vice president of product development for Dallas Semiconductor.

To access a computer, wearers touch a designated contact point so the chip in the ring can communicate with chips inside the computer. Information can be read and written with a momentary contact, allowing information to be updated instantly and travel with a person.

Each ring is individually numbered and registered with a 64-bit serial number that is permanently engraved in the silicon chip to provide absolute authentication.

The first decoder rings were worn by stockroom pickers who recorded items taken off shelves by touching their ring to a simple probe, recording who removed which item at what time and leaving a record of the transaction in the chip. The information was then deposited in a personal computer fitted with a touch memory probe, which enabled inventory reports to be generated automatically.

Sterling silver rings, with a 65-bit memory chip, start at $59.50. But the companies are also developing a stainless steel version that will sell for less than half the price, said Syd Coppersmith, a spokeswoman for Dallas Semiconductor.

The probe reader on the computer exterior or the office wall would only cost a few extra dollars, she said.

Ms. Coppersmith said the rings probably won't be available at retail outlets for another 12 to 18 months. To order the rings, or to obtain more information, prospective buyers should contact Jim Halt, a Jostens sales consultant, at 214-528-9200.

Meanwhile, a Canadian vending machine manufacturer is developing a "cash key" using chips produced by Dallas Semiconductor. Instead of inserting bills or coins into the vending machine, a person could use the key to touch a designated spot on the machine to buy himself a cup of coffee or a can of soda.

Denis Laniel, vice president of Laniel Canada, said the technology would be ideal for vending machines in factories or offices. The employee could load the key at a separate machine by putting in $20 or so. In this way, employees wouldn't have to fish for change whenever they wanted to make a purchase, he said. The machines could also be programmed so that employees arriving before the start of normal working hours could get a free cup of coffee, he said.

"It's a huge market," he added.