Research object: technical systems adequately described by the queueing models. It was determined the characteristic of summary volume for single linear and multilinear service systems with limits when the suggestions are different regarding to the character of service time dependence from the message length. There was developed the dialogue sustem of determing characteristics of stationar systems for queueing messages of random length with the simple input flowAvailable from VNTIC / VNTIC - Scientific & Technical Information Centre of RussiaSIGLERURussian Federatio