This paper presents the assessment of a dialogue system which is used daily by a blind telephone switchboard operator. The purpose of the system is to provide this operator with some information about company members called by external correspondents (phone extensions, department...). In order to realize this system, we have to solved two main problems: on the one hand the recognition of confusable letters (like P and T) and on the second hand, the access to a database with a name -possibly misspelled -. In the paper, we present the assessment which allowed us to measure the system performances but also to validate the two methods designed for this project.