Who is this, please?

This is ...

... speaking.

I'll phone back later.

I've got the wrong number.

Please leave a message after the beep.

Can I take a message?

Can I speak to ..., please?

Just a moment, please.

I'll ring you at about ...

Thank you for ringing.

I must ring off now.

I can't get through. The line's busy.

There is no reply.

This is a bad connection.

Can I use my mobile?