Zeinab  Al-`Alawani, Instructor of Fiqh and Islamic Studies,Graduate School of Islamic and Social Sciences, states the following: “The prophet (peace and blessings be upon him) said, “whenever a man and a woman are alone in one place, their third will be the Shaitan (devil).”
From this hadith we understand that the physical khulwa constitutes the seclusion of a man and a non-mahram woman in a closed area where they cannot be seen by others.
From the Qur’an and the practice of Prophet Muhammad (peace and blessings be upon him) as well as the companions (may Allah be pleased with them) we learn that the early Muslim generation interacted with one another for many reasons such as da`wah, business, education, even health while observing Islamic ethics and teachings of dealing with members of the opposite gender.
So, e-mails, telephones, fax, etc. are means of interaction: as long as we know our limits and we trust one another, the ruling of khalwah does not apply. We need to strike a balance between positive interaction that is governed and regulated by the teachings and manners of Islam and being too rigid to deal with members of the opposite gender.”