KISS (Keep It Simple, Stupid[1]) is a protocol for communicating with a serial terminal node controller (TNC) device used for amateur radio.
[1] The KISS protocol is designed to be easy to implement in simple embedded devices, which are capable of asynchronous serial communications.
While it allows arbitrary data to be transferred, there is no support for flow control or error handling.
This allows the recipient (usually the TNC) to avoid misinterpreting subsequent data as part of a valid frame.
"In multi-port TNCs, the upper 4 bits of the type indicator byte can specify one of up to sixteen ports.