Kantronics KPC–3 Plus User Manual page 133

When a K-Net node has data to send to the other nodes in the stack, it first checks the
RTS line for a true (logic high) state. If RTS is true, then the node drops CTS and the
data is sent to the other nodes in the stack. The dropping of CTS by any node in the
stack will inhibit all the other nodes from using the serial port by forcing RTS false (logic
low), thus avoiding data collisions within the node stack. The additional hardware
required for this operation is commonly referred to as a Diode-Matrix.
K-Net Diode Matrix
A three, four, five, or six serial port Diode Matrix follows the same logic as above, with
six ports probably being about the limit of practicality. The number of diodes required for
a Diode Matrix with N serial ports is 2*N*(N-1).
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