Each network module supports up to 30 digital modems. These network modules use either single or dual Integrated Services Digital Network Primary Rate Interface (ISDN PRI) network modules, Fast Ethernet/PRI combo network module or Basic Rate Interface (BRI) Network Modules to support remote modem users at speeds up to 56 Kbps - up to 30 per Cisco 3620, up to 60 per Cisco 3640 chassis with dual PRI configuration. The modules support multiple LAN technologies, including Ethernet, Fast Ethernet and Token Ring.The internal digital modem network module is available with 6, 12, 18, 24, and 30 pre-installed modem configurations that are field-upgradeable to 30 modems by adding additional modem modules. This provides maximum dial solution expansion for a growing remote user base.Support for the new V.90 modem technology allows users to achieve maximum data transfer rates, while still allowing support for V.34 technologies. The modems are software upgradeable and can support future standards as they become available. High-speed capability ensures rapid download of Web pages and files. Each network module supports up to five modem modules, each of which supports six modems, for a total capacity of 30 digital modems per network module.