Donald H. Till, director of communications for The Washington Post and a recognized expert in satellite and ground communications for newspapers and wire services, collapsed at his son's London home May 31 and was pronounced dead of an apparent heart attack. He was 56.

Mr. Till, who was also communications vice president of the Los Angeles Times-Washington Post News Service, was a resident of Fairfax. He and his wife Isobel were attending a birthday party for their oldest son, Phillip, European radio correspondent for NBC News, when he was stricken.

A native of England, Mr. Till was a communications manager for United Press International in Europe and New York before resigning in 1975 to join Extel Corp. in Chicago.

He joined the Post and L.A. Times-Post news service in Washington two years later.

Mr. Till was active in the American Newspaper Publishers Association and served as vice chairman of the London-based International Press Telecommunications Council. He was in Lisbon last week for an IPTC meeting, and was en route to Washington via London.

Cal Thornton, president and editorial director of Times-Post News Service, said, "The loss of Don Till is deeply shocking to his many friends and colleagues in the industry."

Survivors include his wife; four sons, Phillip, Robert, a resident of Australia, Colin, of Manassas, and Martin, of Fairfax; a daughter, Isabel Gillespie of Manassas, and two grandchildren.