Telephone conversation at the summons of the bell! (4,4)

'telephone' is the definition.
(I know that toll call is a type of long distance)

'conversation at the summons of the bell' is the wordplay.
I cannot quite understand how this works, but
'the' could be 't' (the is pronounced as a 't' sound in some dialects) and 't' is located in the answer.
'summons' could be 'call' (I've seen this in another clue) and 'call' is found in the answer.
'of' could be 'o' and 'o' is located in the answer.
This explanation may well be incorrect...

Can you help me to learn more?