Even if the Internet is associated with well known application protocols like HTTP, FTP or POP3 also own application protocols may be used for data transfer. Neither TCP nor IP care about the data they are carrying - their only purpose is to guarantee the consistency of the data. By this way devices that already use communication protocols can be enhanced to be Internet compatible. The existing communication protocol is embedded in TCP packets and delivered to the receiver via the Internet. But some additional aspects of the Internet have to taken into consideration:

• The runtime of any TCP packet is unpredictable and depending of the network itself e.g. how many data is currently transferred or of the amount of network nodes a packet passes.
• Some packets may get lost or may be delivered out of order. Although TCP corrects these errors the retransmission of packets is possible and causes delays.
• There is hardware like some firewalls or routers which do not support the usage of “unknown” protocols.

To integrate the Internet functionality in the device it is enhanced by the protocols and methods to access the network, for instance by a modem or an Ethernet network. At the receiver's side the evaluation software has be enhanced to use the PC's TCP/IP software stack.




Advantages

• The existing software at the client's and the PC's side can be used.

Disadvantages

• A proprietary software is always required at the PC's side
• Not suitable for all combinations of application protocols and network infrastructure