A communication system comprising: an information terminal ; and a printing apparatus , wherein the information terminal and the printing apparatus belong to a group which may participate in intergroup communication, the group comprising only specific users or apparatuses, wherein the printing apparatus is configured to perform said intergroup communication with the information terminal and includes a printing part configured to perform printing, a communication controller configured to control object data transmission and reception with the information terminal using context data, the context data comprising: i) identification information for identifying the object and ii) position information indicating an output position of the object at a time of printing or display; a data receiver configured to receive print data from the information terminal via the intergroup communication, and a print controller configured to control the printing part using the received print data, wherein the context data comprises a header region, comprising the identification information for identifying the object, and a data region, wherein the data region comprises: element information; combination information defining a combination of the element information; and expansion information comprising mapping information that defines an expansion process performed in a transmission destination of the context data. an information terminal ; and a printing apparatus , wherein the information terminal and the printing apparatus belong to a group which may participate in intergroup communication, the group comprising only specific users or apparatuses, wherein the printing apparatus is configured to perform said intergroup communication with the information terminal and includes a printing part configured to perform printing, a communication controller configured to control object data transmission and reception with the information terminal using context data, the context data comprising: i) identification information for identifying the object and ii) position information indicating an output position of the object at a time of printing or display; a data receiver configured to receive print data from the information terminal via the intergroup communication, and a print controller configured to control the printing part using the received print data, a printing part configured to perform printing, a communication controller configured to control object data transmission and reception with the information terminal using context data, the context data comprising: i) identification information for identifying the object and ii) position information indicating an output position of the object at a time of printing or display; a data receiver configured to receive print data from the information terminal via the intergroup communication, and a print controller configured to control the printing part using the received print data, wherein the context data comprises a header region, comprising the identification information for identifying the object, and a data region, wherein the data region comprises: element information; combination information defining a combination of the element information; and expansion information comprising mapping information that defines an expansion process performed in a transmission destination of the context data. element information; combination information defining a combination of the element information; and expansion information comprising mapping information that defines an expansion process performed in a transmission destination of the context data. <EOS>