Although this type of communication has been mostly replaced since its introduction over 100 years ago by other means of communication it is still used by amateur radio operators as well as some military services.
このタイプの通信は、100年以上前の導入以来、他の通信手段に置き換えられてきたが、現在でもアマチュア無線や一部の軍事通信で使用されている。