An unified approach to signal transmission based on adaptive observers and passification is extended to nonpassifiable nonlinear systems, particularly to systems with relative degree greater than one. Two versions of signal transmission scheme are proposed based on augmented error adaptive observer and high-order tuners. Conditions of parametric convergence of the message estimation for the noiseless case and robustness of the scheme to the bounded channel noise are established. An example of information transmission by means of Lorenz system is given.