In probability theory, the telegraph process is a memoryless continuous-time stochastic process that shows two distinct values. It models burst noise (also called popcorn noise or random telegraph signal). If the two possible values that a random variable can take are and , then the process can be described by the following master equations: and where is the transition rate for going from state to state and is the transition rate for going from going from state to state . The process is also known under the names Kac process (after mathematician Mark Kac), and dichotomous random process.