7.1.3. Hardware flow control
This flow control function is performed by using the control lines RTS(Request To
Send), CTS(Cleat To Send), TXD, RXD and GND in RS232. When the DTE has data to
be transmitted, After the DTE sends RTS signal to the DCE, the DTE waits for a CTS
signal from the DCE. If the DTE receives a CTS signal from the DCE, the DTE transmits
data. When the DCE is receiving data from the DTE, to prevent received data from
exceeding the buffer capacity in the DCE, the DCE sends command of transmission halt
request that is the CTS signal to the DTE. When the buffers have room to receive data
again, The DCE sends command of transmission request which is the CTS signal to the
DTE.
Figure 7.3. Data and Control signal flow in Hardware flow control
Figure 7.4. Pin connection for Hardware flow control
