[RC232] When the MAC layer has a packet to send, it will use a carrier-sense-multiple-access (CSMA) protocol to determine if another module is already transmitting. If another module is transmitting, the module will receive that data before attempting to transmit its data again. If, during this process, the UART receive buffer gets full, the CTS line will go high to prevent the host UART from over-running the receive buffer. The CSMA mechanism introduces a variable delay to the transmission channel. This delay is the sum of a random period and a weighted period that is dependent on the number of times that the module has tried and failed to acquire the channel. For applications that guarantee that only one module will be transmitting at any given time, the CSMA mechanism can be turned off to avoid this delay.