Margaret, whatever have you done to your hair?

AFTER years of speculating on what it would be like to actually see the person you were talking to on the telephone, the age of the videophone is at last upon us. Three Japanese companies, Mitsubishi, Panasonic, and Sony, now have the technology and product to put such an image in front of us.

The VisiTel visual telephone by Mitsubishi was the first. It was introduced in the United States about six months ago, to sell at a suggested retail price of $399. It's now available nationwide through 450 retail stores, including Bloomingdale's in New York and Lechmere in Boston.

``It was an American idea,'' says Tim Beck, national sales manager of the Telecom Division of Mitsubishi Electric Sales America Inc., in Santa Clara, Calif.

``For four years the concept was researched and developed in California, and the design work done by US engineers.''

Although parts are made in both Japan and California, final assembly is done in this country. Mitsubishi developed the videophone transmission standards approved by the Japanese Telecommunication Technology Committee. Mitsubishi has licensed the technology to Panasonic - but not, as yet, to any American manufacturer.

The Panasonic videophone models will be available in November to retail at $449.95 and $469.95. A Sony model will arrive in September to retail for about $400.

The products of the three companies are compatible. All models can transmit and receive still black-and-white images, although the videophones of each company use a different type of camera. Each camera transmits a still or freeze-frame black-and-white image every five to seven seconds over standard telephone lines to screens that are four to five inches wide.

The cameras will also transfer information such as contracts, illustrations, and drawings via these ``video snapshots.''

``By providing a visual connection between two parties,'' says Michael Troetti, national sales manager of Panasonic, ``we are making telephone conversations more personal than ever.

``With our new videophone and video monitor, a little boy in New York will be able to both talk with and see his grandmother in California. People separated by distance from families and friends will be likely customers, as well as people who operate out of at-home offices.''

American sales projections for 1989 vary from a conservative 70,000 units to 175,000 units.

``There is a lot of high technology in this picture phone product,'' says Mr. Beck, ``so it will be a while before prices come down significantly. Maybe in three to four years we will be able to offer a $299 model.''

Beck says that the VisiTel videophone works in tandem with any home telephone that is equipped with a modular phone plug. It plugs into a regular AC outlet and home phone jack and requires no special wiring or phone line. The user is in control of the outgoing image.

To operate, the caller simply positions himself in front of the unit's camera lens, views his image on the screen, and then he pushes the SEND button to transmit his picture to another VisiTel user. Image transmission takes about five seconds, and callers can exchange pictures as often as desired.

Many people see the new videophones as the boldest step into the next generation of telecommunications since the invention of the telephone itself - one of the devices that has changed the world most significantly.