Couple on the phone, maybe (4)

I believe the answer is:

dial

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'couple on the phone' is the definition.
'Dial' can be an answer for 'phone' (I've seen this before). I'm not sure about the 'couple on the' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for dial that I've seen before include "Indicator" , "Ring the clock-face" , "Meter face" , "Calibrated face" , "Clock face" .)

I've seen this clue in the Evening Standard.

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