Modem 常用AT指令集(11) &Gn - Select Guard Tone 选择保护音 &G0 Disable guard tone. &G1 Disable guard tone. &G2 Enable 1800 Hz guard tone.&Jn - Telephone Jack Control 外接电话控制 &J0 Set S-Register response only for compatibility. &J1 Set S-Register response only for compatibility.&Kn - Flow Control 流量控制 &K0 Disable DTE/DCE flow control. &K3 Enable RTS/CTS DTE/DCE flow control.使用RTS/CTS DTE/DCE进行流量控制 &K4 Enable XON/XOFF DTE/DCE flow control. &K5 Enable transparent XON/XOFF flow control. &K6 Enable both RTS/CTS and XON/XOFF flow control.&Ln - Leased Line Operation 租用电话线操作