Green’s Dictionary of Slang

eau-de-Cologne n.

[rhy. sl. ]

1. the telephone.

[UK]J. Gosling Ghost Squad 25: Thieves’ argot, spoken properly, is a foreign language which needs to be learned [...] a phone can be either ‘trombone’ or ‘Eau de Cologne’.
[Aus]‘Whisper+ All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxiv 4/4: eau de cologne: Phone.
[UK]Dodson & Saczek Dict. of Cockney Rhy. Sl. 27: eau de Cologne. ’phone; reduced to ‘eau de’ (ordour) (Aus.).
[Aus]R. Aven-Bray Ridgey-Didge Oz Jack Lang 27: Eau De Cologne Phone.
[Aus]Tupper & Wortley Aus. Prison Sl. Gloss. [Internet] Eau de Cologne. Rhyming slang for telephone. In addition to the conventional telephone this expression is also used to describe the communication system established by prisoners which relies on the emptying of cell toilets and speaking through the emptied conduit. Note the (perhaps unintentional) play on words (eau de Cologne = toilet water).
[Aus]Pete’s Aussie Sl. Home Page [Internet] Eau de Cologne: the ’phone.

2. a woman [= polone n. (1)].

[UK]R. Puxley Fresh Rabbit.