Ethernet modem - mod-IP carries out the AT Hayes commands sent to it by a serial port and in the reply it sends adequate messages, such as a typical analog modem. The serial interface signal lines behave also as in the case of simple modems. This manner of work allows for establishing the connection through Ethernet without the modification of the supervising program in PC, if PC has controlled the analog modem to date. The processes using modIP will not see any difference in handling in relation to modem connections through telephone lines. This mode of work is especially comfortable in the situations when the operating system needs to be used, when the use of network is hampered or impossible e.g. DOS.

Virtual serial port - in this mode mod-IP along with the driver installed in the computer constitute the data transmission channel, functionally corresponding to the serial cable with the length limited only with the access to the Ethernet network.

Network converter, server - mod-IP waits for establishing the connection initiated by other network facilities and then transmitting data between the serial port and the network.

Serial converter, client - mod-IP automatically establishes the connection with a relevant network device for data transmission from the serial port to a remote device. Of course the data are transmitted in both directions.