These are what is called the "Hallmark". All silver articles made in Britain have to have a Hallmark. It identifies where it was made and the year of making. It is a complicated system, there are books written about it. I'm sure you can get details from Google as well. Further answer: when you specified an "old sterling silver ring", I assumed it was British, but of course it might have come from elsewhere. Other countries have their own systems of hallmarking. A useful site is "www.925-1000.com" which gives details of the marks of many countries as well as Britain, so you should be able to find what you have on your ring.
It may mean that the ring is made of sterling silver.
The number "82" on a silver ring might signify its purity, indicating 82.5% silver content, commonly known as sterling silver. Sterling silver jewelry contains 92.5% pure silver mixed with 7.5% of other metals. It's a standard mark denoting high-quality silver jewelry.
Look to see if 925 is engraved inside the ring, if it is it is made from sterling silver.
PAD 925 for a sterling silver ring describes the chemical makeup of the silver in the ring. Generally the number correlate to percentages of metal in the silver alloy.
Can a ruby be real in a sterling silver ring
The 925 hallmark is indicative of 92.5% Sterling Silver.
A person can determine whether a sterling silver ring is genuine by dropping their ring into a bowl of vinegar. If it isn't silver, a reaction will occur.
Sterling silver
if the number .925 is stamped on it also that means sterling silver if the number .999 is stamped on the ring that means it is pure silver if no numbers, i am not sure
usually, sterling means silver
What does CI mean on a ring
plated sterling silver