TAT - 1 , the first submarine transatlantic telephone cable carried messages from Washington to London .
The primary circuit was routed from Washington , D.C. via London , Copenhagen , Stockholm and Helsinki to Moscow .
TAT - 1 , the first submarine transatlantic telephone cable carried messages from Washington , D.C. to London .
The primary circuit was routed from Washington , D.C. via London , Copenhagen , Stockholm and Helsinki to Moscow .