To say that telephony is in a state of transition is to describe the history of telephony. It always has been in a state of transition and will continue so for the foreseeable future. As the world has been increasingly compressed in size through television and telecommunications, the trend of telephony standards has been toward enabling worldwide application rather than having each national network go its own way. While national networks still are interconnected through gateways, primarily for billing control, international signaling systems are becoming standardized with only minor national differences.
KeywordsMicrowave Radar Dial Acoustics
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