HylaFAX is a fax and paging system for Unix. It supports sending facsimile, receiving facsimile, polled retrieval of facsimile, transparent shared data use of the modem and sending alpha-numeric pages. The software is structured around a client-server architecture. Fax modems may reside on a single machine on a network and clients can submit outbound jobs from any machine that can communicate with the machine on which the modems reside. An access control mechanism is included to control which users on which machines may access a server.