dial train拨号音: dial tone; trunk tone中继线: junction line; relay line; t ...忙音中继线: busy tone trunk; tone trunk长途拨号中继线: toll dialing trunk反向拨号中继线: dial back trunk下载手机词典可随时随地查词查翻译关注微信公众号：chachacidian，回复:拨号音中继线，即可在微信中查询翻译
