First, in the Cisco Remote Access server, with three pairs of lines to connect the DTE and DCE, each pair of lines, one sent,
a receipt:
1. TX/RX Data transmission Line
Send: Dte->tx->dce
Receive: Dte<-rx<-dce
DCE device (MODEM) sends data to DTE via RX, receives data from DTE via TX, sends
The rate of reception is set on the modem. The modem and router speeds connected by RS232 must be consistent.
2, Rts/cts hardware flow control
Dte->rts->dce
Dte<-cts<-dce
When the DTE data cache is full, the RTS signal will be lowered to notify DCE not to send the data, and, similarly, DCE will
Reduce the CTS signal and notify the DTE not to send data. Modem and access server must be set to hardware flow control
。
3, DTR/DCD Modem control
Dte->rts->dce
Dte<-dcd<-dce
When the remote access server (DTE) READY,DTR output signal is high, by lowering the DTR signal,
The remote access server hangs off the line. Modem through the DCD signal to the DTE, show that there is a dial-up dial in, need far
Access server to provide services, the modem's DCD signal disappeared, indicating that the modem lost the dial.