When the receiver is ready for more input, it asserts RTS requesting the other side to resume sending. That is, the RTS pin on one end of the cable is connected to the CTS pin at the other end. While this may seem confusing, there are valid historical reasons for this which are too involved to discuss here. For DTR flow control at a terminal, the DTR signal is like the signal sent from the RTS pin. This DTR pin should connects to the host's CTS pin.
Many terminals use DTR flow control.
This is only one-way flow control to keep the terminal from being overrun. It doesn't protect the computer from someone typing too fast for the computer to handle it. In a standard null modem cable the DTR pin at the terminal is connected to the DSR pin at the computer. The fact that it's only one way will not affect anything so long as the host doesn't get overwhelmed by your typing speed and drop RTS in a vain attempt to lock your keyboard. See Keyboard Lock .