<P> The codes , developed in 1937 and expanded in 1974 by the Association of Public - Safety Communications Officials - International ( APCO ) , allow brevity and standardization of message traffic . They have historically been widely used by law enforcement officers in North America , but , due to the lack of standardization , in 2006 the U.S. federal government recommended they be discontinued in favor of everyday language . </P>
<P> The codes , developed in 1937 and expanded in 1974 by the Association of Public - Safety Communications Officials - International ( APCO ) , allow brevity and standardization of message traffic . They have historically been widely used by law enforcement officers in North America , but , due to the lack of standardization , in 2006 the U.S. federal government recommended they be discontinued in favor of everyday language . </P>
where does the saying ten four come from
where does the saying ten four come from
the Association of Public - Safety Communications Officials - International
the Association of Public - Safety Communications Officials - International