AeroComm CL4424 - Manual (Page 14)

CL4424 User’s Manual
6/21/2005 14
2.3 Hardware Flow Control
Often, the host device can send data to the CL4424 faster than it can be sent over the RF. The
CL4424 has a 256 byte buffer to store data before sending it over the RF. If the host device is
sending data faster than the CL4424 can send it out, eventually, the buffer will fill up. If the host
device continues to send data while the CL4424 buffer is full, that data will be discarded. To
avoid this situation, the CL4424 will de-assert CTS as a warning that the buffer is filling. The host
device should stop sending data. When the CL4424 is able to free some buffer space, it will
assert CTS and the host device can continue sending data. Similarly, if RTS is enabled in the
CL4424, the host device can throttle the CL4424 by de-asserting RTS. Note: CTS is always
enabled by default. RS-485 Interface does not support Hardware flow control and RTS mode
should not be enabled on a RS-485 CL4424.