Internationally, analog telephone connections are just as common in the business world as the predominant ISDN connections in Germany. The operation of international networks thus places particular demands on remote maintenance options and for high-availability of the gateways and thus requires different interfaces than the ISDN common in Germany. Apart from conventional analog telephone lines, mobile telephone networks such as GSM or GPRS may, in certain cases, represent the only way of providing remote maintenance without broadband or other cabled access. In response to these requirements, most LANCOM models with a serial interface can be extended with an additional WAN interface with the use of analog modems, GSM or GPRS.