My friends live in other places: other neighborhoods, other towns, other states. When we get together, it is often our fingers that do the walking from one home to the other.

For us, the telephone is a meeting hall, a neighborhood, the way we keep our small community together. By voice, we do the maintenance that keeps friendships alive, and sometimes families.

This is called, in our culture, keeping in touch.

Yet I sometimes wonder whether there isn't a hidden cost to this piece of technology, too. I don't mean the costs of intrusion. It's true that the phone insults our quiet and insists its way into our privacy. But I will trade that for this lifeline.

Nor do I mean the cost that shows up on my bill. I rationalize that easily with friends from other area codes: long distance is cheaper than planes or therapy . . . or disconnection.

But isn't it possible that this staple of modern life has had some odd consequences for us? Isn't it possible that the instrument has actually been an actor in our culture over a century?

John Staudenmaier, a Jesuit and visiting assistant professor at MIT's center for Science, Technology and Society, talks about the birth of the phone in 1876 as "the first time in human history that we could split voice from sight, touch, smell and taste."

What does that mean to us? That we no longer have to be in the same room to talk to each other. That we can choose friends across space and keep friends over distance.

But doesn't it also mean that we can ignore the people who live in our hallway? In some ways, the same machine that offers us a handy shortcut through loneliness may also make it more likely for us to live alone.

"The hometown, the street and neighborhood have also been eroded particularly by the telephone," believes Staudenmaier, "because the real relationships in my life are not the people on my street and not the people in my apartment building. They can be strangers because I have 'real' friends connected by electronic rather than physical bodily connections."

It isn't just the phone that does this, I know. The car, the television set and manufacturing have also changed us so we live more in the wide world and less on our own block.

But I suspect that this odd and utterly routine ability to communicate by sound alone has altered another piece of our human psyche. We are more able now to protect and distance ourselves in human communication.

How skillfully have we learned to control our voices and hide our emotions? How How often do we use the phone so we won't have to, literally, face each other? I know a woman who bought a portable phone so that she could garden or scrub the sink or unload the dishwasher when her mother called. I know a man who regularly broke up with the women in his life by phone because it was so much easier.

I am no Luddite, raging against electronics. In my home there are four extension phones, a hundred feet of cord and one teen-ager. I work by phone, send my column from one city to another by phone. I maintain--though I never make-- friendships by phone.

Yet, I think it's crucial to remember the limits, to remember the trade-offs of the technology we live with. The telephone company encourages us to reach out and touch someone. Funny, that's one thing we can't do by phone.