Assuming a class of continuous-time observers is known for a given non-linear system, an observation structure is derived when sensors information is subject to network-induced communication constraints. The approach is based on the recent results on hybrid observers for sampled-data systems by Karafyllis and Kravaris (2009). Considering two classes of protocols, some asymptotic stability properties are shown to hold for the observation error, under some conditions, and explicit bounds on the maximum allowable transmission interval are given.