WEST ISLIP, N.Y. (AP) _ E.T., phone home - it won't cost you anything from a Long Island Expressway rest stop near exit 52.

New York Telephone on Thursday finally caught up with two dozen ''pay'' telephones that were operating free of charge and letting those in the know call friends and relatives all over the world.

Police alerted the phone company after a man who lived 50 miles away was wounded at the rest stop in a hold-up attempt.

When police asked the victim, Waseem Moosa of New York City, what he was doing so far from home at 1:30 a.m. Wednesday, he admitted he had driven the distance to make a phone call to Pakistan.

Skeptical officers returned to the area to look for witnesses to the robbery, and discovered 15 Pakistani men using the phones. Police then notified the phone company, which reprogrammed the phones.

''It was a boo-boo, a human error in which somewhere down the line the pay phones were not given a proper code with the main computer in Commack,'' said phone company spokesman Bruce Reisman.

Reisman guessed the calls were made throughout May, adding that New York Telephone normally doesn't benefit from international calls. Since the break- up of AT&T in 1984, New York Telephone offers only local service.

AT&T spokeswoman Laura Abbot said the incident was under investigation, and that her company and New York Telephone will determine which one will be stuck with the bill.

Abbot could not say how many calls were made from the free phones or how much they were worth.