diànhuà / jiētōng / qián / zhǔjiàofāng / tīngdào / de / huílíngyīn / shì / biāozhǔn / de / chángyīn

电话接通前，主叫方听到的回铃音是标准的长音。

Before the call is connected, the ringback tone heard by the caller is a standard long tone.