ああ もしもし

Oh, hello?

→ ああ
phrase Rare #40,623
Oh, hello? Used as a casual greeting or acknowledgment when answering the phone. ああ adds a sense of recognition or acknowledgment.
JA: ああ もしもし、俺だ。どうした?
EN: Oh, hello? It’s me. What’s up?

ああもしもし?

Ah, hello?

— セッション (2014)

ああもしもし

Oh, hello?

— High and Low (1963)

ああもしもし戸倉ですはあはあ…え?

Oh, hello? This is Tokura. Uh-huh, uh-huh... What?

— High and Low (1963)

ああもしもし俺だどうした?

Ah, hello? It's me. What's up?

— High and Low (1963)