August 23, 1983

The Government today lowered the maximum interest rate on federally backed home mortgages to 13 percent, from 13.5 percent. The reduction in the closely watched rate halts a trend of increases that began in early June, when it stood at a three-year low of 11.5 percent. The new 13 percent rate is effective on single-family home mortgages insured by the Federal Housing Administration and the Veterans Administration.

The tentative agreement to end the nationwide strike against the American Telephone and Telegraph Company is likely to lead to slightly higher phone rates because wage increases will be passed on to consumers, company and union officials and analysts said yesterday. However, the rate increases, of perhaps a few percentage points, would be small compared with those already expected from the structural changes taking place in the telephone business as a result of the pending breakup of A.T.& T. and recent decisions by the Federal Communications Commission. Those changes are expected to lead to at least a doubling of local telephone rates in the next year or two. ''It's fair to assume that if wages go up, rates will go up a commensurate amount,'' said Paul L. Gioia, chairman of the New York State Public Service Commission, which regulates telephone rates in the state. He added, however, ''If wages go up 5 percent in one year I don't think that's significant. That's in line with general economic circumstances.''

Informed that he was engaging in unlawful activity and could get a summons, Antoine Williams moved on. Antoine explained that receiving a ticket would be no small matter. He would be in trouble with his mom. Antoine, who is 7 years old, was playing football on the lawn of an apartment building, an activity strictly prohibited by the latest edict from Mayor Thomas H. Cooke Jr. in his ''war on blight.'' The Mayor cracked down a few days ago on ''the spectacle of young children'' playing outside apartment buildings and on their turning the nice, green lawns here into ''dust bowls'' and ''pigpens.''

Quotation of the Day ''The debates represent a breakthrough in the way the Democratic Party selects its Presidential candidate.

International A new trade-policy dispute has erupted within the Administration. The subject is an export license sought by a British-owned Houston-based company to ship a $40 million offshore marine mooring system to Libya. The Commerce Department is in favor of the sale, officials said, while the State Department opposes it. The dispute comes just days after the resolution of one dealing with sales of pipeline-laying equipment to the Soviet Union. (Page A1.) Mexico, after a year of financial crisis, has overcome an early sense of panic and is now resigned to a combination of economic difficulties and the social hardships they have created. Along with austerity, however, there is cautious hope for the future. (A1.) Mexico announced compensation terms for 11 of the 57 private banks and credit institutions that were nationalized last year. (D15.)