The invention relates to a method for the data communication between a portable data carrier (10) and an external communication device, which both in each case comprise a TCP/IP protocol stack (24). In a first step the communication device sends communication data to the data carrier (10), the communication data comprising at least commands according to an Internet protocol of the application layer of the TCP/IP reference model and commands in the form of APDUs according to ISO/IEC 7816-4. The method additionally comprises the steps of transmitting the communication data between the communication device and the data carrier (10), of receiving the communication data by the data carrier (10) and of separating the received APDUs and the received Internet protocol commands from each other by means of the allocator unit (32) of the data carrier (10). Here, the mentioned commands are transmitted by means of TCP/IP and the allocator unit (32) separates the APDUs and the Internet protocol commands not until above the transport layer of the TCP/IP reference model. This permits the APDUs and the Internet protocol commands transmitted together with said APDUs in a joint TCP/IP data stream to be separated from each other in a simple fashion.