The fear of being buried alive has led to the invention of various devices whose purpose was to allow the hastily-entombed to signal that a mistake had been made. It wasn't a misplaced fear either -- even in this century, physicians of solid repute have cited numerous instances of people being pronounced dead and then stirring to life again, reviving from a coma or some trauma that had reduced the pulse or respiration to imperceptibility.
In the 18th and 19th centuries, contraptions employing bells, buzzers and flags were devised to send such distress signals. As technology advanced, so did what people wanted to take to their graves as a precaution against such an eventuality. These days it's telephones and modems.
The last will of David Hughes provides for a laptop computer powered by a solar electric panel and linked by radio with computer networks throughout the world to be buried with him. Though his stated purpose is to continue to interact with the living even after his demise, one could see that such a connection would also serve him in the case of premature burial.
Mary Baker Eddy was long rumored to have a telephone installed in her crypt, but this has proved out to be only folklore. During the building of her monument at Mount Auburn Cemetery in Boston, her body was kept in that cemetery's general receiving vault. A guard was hired to stay with the body until it was interred and the tomb sealed, and a telephone was installed at the receiving vault for his use during that period. There was never a phone at her monument.
Our legend of the deceased husband summoning his wife to his side plays upon our fascination with the supernatural. We don't want to believe death is the end of things, so we embrace stories that seem to confirm it won't be. If communication between the dead and the living is possible, then death must not be all that final a destination.
Phone or no phone, to date there's no confirmed instance of contact being made from beyond the grave.
Variations:
The dead man is variously described as an unnamed Englishman, a wealthy retired British businessman or one of the Ball brothers (American).
The husband is interred in a crypt or buried in a coffin.
The wife dies two years after her husband, the implication being that when it was her time to die, he called to tell her so.
