USAGE: get_transfunc idChan DBUser DBPassword DBService [time]
      idChan is the channel for which the caller wishes to retrieve a 
       transfer function
      DBUser is the Database User to use to access the DB.
      DBPassword  is the password of DBUser.
      DBService is the service ID of the database.
      time(optional) is the time for which the caller wants the transfer
       function for the channel.  If no time is given, then the desired
       time is assumed to be Now.  (seconds since 1970).