I am working as a contractor in the US here remotely full time and I communicate with my team through Skype. Usually we receive the requirements for a project once a week and we dash off to do our own work.
Can the person whom I report to request that I be availble on all the time? If I were a full time employee, then that would be a valid request. But I am not sure for contractors.
One time my manager was complaining to me that I wasn't responsive in Skype.