Sometimes for the senior positions, interview is conducted on telephone. This happens when the decision maker is located at a far off place (may be in foreign country) and traveling cost and time is involved in arranging face-to-face interview. So a preliminary interview is conducted on telephone.
One tip that I can give is to take excuse from the interviewer for the immediate interview. You might be busy in the meeting; you might be stuck in the traffic jam; you might be working on important project etc. Request the interviewer to call you in an hour’s time or take his/her number and call back.
During this time, get in touch with the mastermind group and seek their guidance. Gain poise and serenity and go to some place where there’s no noise and unwanted intrusion. Wait for the call or call back. Keep pen and paper handy with you for taking notes.