話はなし中ちゅう

は

な

し

ちゅ

う

Meanings

noun which may take the genitive case particle 'no'

busy (phone); line engaged

Used for a phone line that is currently in use; equivalent to 'the line is busy' or 'engaged'.

noun which may take the genitive case particle 'no'

in talks; discussion underway

Indicates that a meeting or discussion is currently in progress; often used in business or formal contexts.

〈人ひと〉の電でん話わが話はなし中ちゅうだsomeone's phone line is busy
田た中なかさんの電でん話わは話はなし中ちゅうでした。
Mr. Tanaka's phone line was busy.
〈人ひと〉は話はなし中ちゅうでsomeone is currently talking/in discussion
彼かれは今いま、上じょう司しと話はなし中ちゅうです。
He is currently talking with his boss.
話はなし中ちゅうのため、〈動どう詞し〉since the line is busy, (do something)
話はなし中ちゅうのため、後あとでかけ直なおします。
Since the line is busy, I'll call back later.
話はなし中ちゅうの音おとがするto hear a busy signal (tone)
電でん話わをかけたが、話はなし中ちゅうの音おとがした。
I called, but got a busy signal.

使し用よう中ちゅう sense 1
使用中 is a general term for something being 'in use' (a phone line, a restroom, etc.), while 話し中 specifically describes a phone line being busy because someone is talking.
取とり込こみ中ちゅう sense 1
取り込み中 means 'busy/occupied' in a broad sense (often due to some urgent matter), whereas 話し中 refers narrowly to a phone line or conversation currently in progress.

お話はなし中ちゅう
お話中 is the polite/formal way to say a phone line is busy, while 話中 is the plain or technical equivalent.

話はなし中ちゅう
Standard spelling; the okurigana し makes the reading clear.
話はなし中ちゅう
Abbreviated spelling; less common but still used, especially in technical or compact contexts.

Compound of 話し (はなし, 'talk') + 中 (ちゅう, 'in the middle of'). The spelling 話中 is a common abbreviation.