Linking serial systems with TCP/IP stack to the Ethernet

Many serial terminal devices are already equipped with their own TCP/IP protocol stack that physically uses a standard point-to-point port such as RS232 in connection with SLIP (Serial Line Internet Protocol). Originally, this option was intended for remote maintenance and configuration over an external modem; today it is in many cases however desirable to integrate such applications into the Ethernet LAN, thereby also availing of an existing WAN access.

In the following application, a telephone system uses SLIP for transfer of your configuration and charge data. To enable a spatially flexible administration of the system, the integration into the Ethernet LAN was implemented by means of a W&T Com-Server working as SLIP router.

Technical background:

As is already apparent from the name "Serial Line Internet Protocol", SLIP offers a way to send IP data traffic including higher-level protocols such as UDP or TCP over a serial point-to-point connection. In terms of the OSI model, SLIP - like Ethernet or token ring - operates on the physical level. In the specific case of a Com-Server working like a SLIP router, this means - depending on the data direction - replacement of the Ethernet protocol frame by a serial SLIP frame or vice-versa.