要建立与内置或集成modem的（在路由器中）的直接连接对话，如CiscoAS5200中Microcom modem所要求的，首先用modem at-mode命令打开直接连接对话，然后向指定modem发送一个AT命令。例如，下例向modem 1/1发AT命令at\s： AS5200# modem at-mode 1/1 You are now entering AT command mode on modem (slot 1 / port 1). Please type CTRL-C to exit AT command mode. at%v MNP Class 10 V.34/V.FC Modem Rev 1.0/85 OK at\s IDLE 000:00:00 LAST DIALNET ADDR: FFFFFFFFFFFF MODEM HW: SA 2W United States 4 RTS 5 CTS 6 DSR - CD 20 DTR - RI MODULATION IDLE MODEM BPS 28800 AT%G0 MODEM FLOW OFF AT\G0 MODEM MODE AUT AT\N3 V.23 OPR. OFF AT