High Quality Content by WIKIPEDIA articles! In probability theory, the telegraph process is a memoryless continuous-time stochastic process that shows two distinct values. If these are called a and b, the process can be described by the following master equations: partial_t P(a, t x, t_0)=-lambda P(a, t x, t_0)+mu P(b, t x, t_0) and partial_t P(b, t x, t_0)=lambda P(a, t x, t_0)-mu P(b, t x, t_0). The process is also known under the names Katz process, dichotomous random process.