104 CHAPTER 4: WAN INTERFACE CONFIGURATIONTheoretically, if the peer (usually an ISP) uses a digital modem, the AM interfacecan establish connection with V.90 Modem standard to provide downstream ratesup to 56 kbps and upstream rates up to 33.6 kbps. If the peer (usually a commonuser) uses an analog modem (or an AM interface), the AM interface can establishconnection with V.34 Modem standard to provide rates (both downstream andupstream) up to 33.6 kbps.The real rate of an AM interface, however, may deviate somewhat depending online quality, PBX performance, connection protocol, and other elements.Configuring an AMInterfaceFollow these steps to configure an AM interface:n To set the baud rate for an AM interface, use the speed command inuser-interface view. Refer to “User Interface Configuration” on page 2155 forrelated information.The configuration of AM interface is similar to that of asynchronous interface andmodem, except that an AM interface does not support the modem auto-answerand the baudrate commands. (Refer to “Modem Configuration” on page 355 forinformation about modem configuration.)You may need to configure parameters concerning PPP, DCC, IP addressing,firewall and backup center. For their configuration, refer “Configuring PPP” onpage 367, “DCC Configuration” on page 153, “IP Addressing Configuration” onpage 623, “Firewall Configuration” on page 1789, and “Backup CenterConfiguration” on page 1961.ISDN BRI InterfaceOverview Technical backgroundIntegrated services digital network (ISDN) is a technology rising in 1970s. Itprovides all-digital terminal-to-terminal services and fulfills the full digitizeddelivery of the services integrated voice, data, graphics and video.ISDN is different from the conventional PSTN network. In a conventional PSTNnetwork, user information is transferred as analog signals over analog user loop toexchanges where these analog signals are converted into digital signals. Thesedigital signals traverse the digital switching and transmission network and areconverted into the analog signals again upon their reach at the destination. ISDNmakes it possible to implement digital transmission on a user loop and fulfills theend-to-end digitalization. As a standardized digital interface, ISDN BRI interfaceTo do... Use the command... RemarksEnter system view system-view --Enter AM interface view interface analogmodemnumberRequiredSet the area code country-code area-name Optionalunited-states by defaultSet asynchronous interfacepropertiesSee “Configuring anAsynchronous SerialInterface” on page 100.Optional
