BETWEEN THEM, the Communications Workers and AT&T have worked out an interesting response to phone employees' anxieties about job security. There's plenty of reason for anxiety, with AT&T about to split off its local operating companies at the end of the year. The questions about security usually come up at the point at which an industry is irretrievably sinking. In this case, for once, they arise in a company as well equipped as any in the world to deal with them. The new labor contract is likely to be cited widely as a precedent.

Job security is, for people who make policy, a dilemma. Too tight and cozy an assurance of the same job, to be done in the same way in the same place forever, and the enterprise loses any flexibility to adjust to changing markets. Too ironclad a promise of the job for life, at a guaranteed wage, and the person who holds it loses all interest in adjustment. Both of those mistakes have been made on a large scale in Western Europe, with its passion for security. A rigid labor market, Europeans have discovered to their distress, generates extremely high unemployment rates in times when the economy is changing.

The phone contract has been designed with these dangers much in mind. The unions and the company are putting their faith, and quite a lot of money, into training for people who want it. It's "not meant for specific jobs," AT&T says, but for the general improvement of skills of people who fear that their present jobs may vanish or who, more frequently, simply want to make their way up the company ladder. In the past AT&T has paid college tuition for employees, but that mainly benefited people moving into managerial or professional jobs. This contract applies the same principle to everyone in the company or, as they will be after Jan. 1, the eight companies.

For people approaching the age of 65, there are substantial improvements in the early retirement system. The effect is, toward the ends of their careers, to take some of the financial pressure off those people who do not wish to move to new jobs and for whom there is not really much economic reason to encourage it. As for closing plants, the contract recognizes that it is sometimes necessary. But it improves the rules controlling reassignment, retraining and relocation allowances.

The wage increases are the least interesting part of this contract. It is enough to say that they lie well within the boundaries of a noninflationary settlement. But the unions said from the beginning that it was security, not wages, about which they were mainly concerned this year. There they and the company seem to have accomplished the feat of simultaneously improving security for the employees and flexibility for management.