PLEADED GUILTY. Richard Berendzen, 51, former president of American University in Washington; to two charges of making obscene telephone calls; in Fairfax, Va. Berendzen abruptly resigned in April during an investigation of lewd calls to a woman in Virginia and was treated at a clinic for sexual disorders. Two 30-day jail terms were suspended on the conditions that Berendzen remain in an outpatient therapy program and report to the court every 90 days for a year.