Next time you pick up your telephone for an important conversation, try not to think of this humbling statistic: There are 181 million telephones in use across the country. That size of market sooner or later attracts designers, of course, and it's perhaps no surprise that today you can buy a designer label telephone -- Pierre Cardin, for example.

People seem to want everything in their environment to reflect their taste -- why not the telephone, which until a few years ago was offered in a depressingly limited number of design choices? A 1968 Federal Communications Commission ruling allowing non-Bell equipment to be hooked up to the Bell System changed all that, and now telephone stores have flooded the market with models that can be changed at a whim.

This year marks a full century since a Boston resident, name and address long forgotten, ordered and received the first home phone. We've progressed from hand-crank models to Pac-Man phones.

The man responsible for the design of millions of phones (but not the Pac-Man model) is Don Genaro, vice president of Henry Dreyfuss Associates, a New York industrial design firm. His company has been designing for Ma Bell since 1930. Genaro says that in designing a phone, he tries to make it as easy to handle as possible. "You should be able to cradle the phone on your shoulder, leaving both hands free to do other things," he says.

In terms of style, we seem to be flush with funny phones -- a mildly whimsical airplane for the aviation buff, or a candlestick phone fashioned from a cartoon character such as Snoopy or Mickey Mouse. But the more serious European sets are also available now. Genaro says, "They are staying with the old tenet, 'Less is more.'" CAPTION: Picture 1, the A78 Communicator from Denmark which looks like a slim book with a handset in it, comes in colors as well as block and costs $119; Picture 2, the Ericaphone, an American designed instrument made by a Swedish firm, secretes a dial ($60) or push buttons ($90) on its base; Picture 3, for $119 you can dial the propeller to get your number. This plane talker comes in a number of colors including aircraft gray. ST: Non-Bell phones at the Telephone Warehouse and other stores; Picture 4, Bell's $175 Big Button is the next best thing to a real live operator for the arthritic and those with bad eyes. It's also for those who just like big numbers, PHOTOGRAPHS BY MARGARET THOMAS