▁remov able ▁c ork - mount ed ▁wh ist le , ▁which ▁could ▁be ▁sound ed ▁by ▁blow ing ▁into ▁the ▁t ube ▁from ▁the ▁other ▁end . ▁On ▁naval ▁vessels , ▁this ▁created ▁a ▁distinct ive ▁sound ▁associated ▁with ▁ur gent ▁int ra - ship ▁communication ▁on ▁old ▁war ships . ▁The ▁sound ▁of ▁the ▁wh ist le ▁would ▁sum mon ▁the ▁listener , ▁who ▁would ▁remove ▁the ▁wh ist le ▁and ▁answer ▁the ▁call . ▁ ▁Vo ice ▁pip es ▁could ▁be ▁used ▁over ▁distances ▁as ▁long ▁as ▁. ▁However , ▁very ▁long ▁speaking ▁tub es ▁might ▁use ▁an ▁elect rical ▁sign alling ▁device ▁to ▁indicate ▁a ▁call , ▁as ▁the ▁large ▁volume ▁of ▁air ▁in ▁the ▁pipe ▁would ▁make ▁it ▁difficult ▁to ▁blow ▁with ▁enough ▁pressure ▁to ▁sound ▁a ▁wh ist le ▁at ▁the ▁far ▁end . ▁Despite ▁this , ▁a ▁pipe ▁with ▁a ▁larger ▁internal ▁diameter ▁was ▁des irable ▁for ▁longer ▁runs ▁as ▁the ▁signal ▁loss ▁is ▁in vers ely ▁proportional ▁to ▁the ▁pipe ' s ▁cross - section al ▁area . ▁ ▁Vo ice pip es ▁have ▁no ▁switching ▁mechanism ▁and ▁so , ▁to ▁provide ▁multiple ▁destin ations , ▁separate ▁voice pip es ▁with ▁dedicated ▁trans it ▁pip es ▁have ▁to ▁be ▁provided ▁between ▁all ▁pairs ▁of ▁desired ▁end points . ▁ ▁The ▁technology ▁continues ▁to ▁be ▁used ▁into ▁the ▁electronic ▁age ▁due ▁to ▁its ▁reli ability ▁and ▁low ▁cost . ▁Vo ice ▁pip es ▁are ▁una ffect ed ▁by ▁a ▁complete ▁elect rical ▁power ▁loss ▁or ▁by