This note is focused on control systems in which the observer is not co-located with the controller and the communication channel between them is of limited bandwidth. Due to the low data rate requirement, the control law must be of simple form. As a result, a tristate distributed controller is examined. The control algorithm is proven to be convergent if the system structure satisfies certain technical conditions. The convergence is robust in, the sense that the system parameters and even the structure of the underlying system dynamics need not to be completely known.