Fixed-mobile convergence (FMC), which allows mobile users the same voice communications inside or outside the office, is in a state of flux right now with a wide range of approaches, partnerships and offerings. The proliferation of smartphones, ubiquitous voice mobility, and enterprise VoIP and Wi-Fi have all spurred the development of FMC. Because workers are coming to expect the same level of communications within the workplace as outside of it, FMC is highly desirable to enterprises for several reasons. It means that employees could always be reached on one device, at one phone number, and with one voice-mail box. Wi-Fi enabled systems can solve the problem of poor reception pockets within the workplace, and FMC can provide access to corporate directories and to PBX features such as hold, transfer, and conferencing. FMC gives companies control of cellular costs (which can no longer be hidden in expense accounts), mobile device selection and management (Nokias E-series and select Windows Mobile-based handsets offer the best broad support), and regulations such as meeting auditor requirements (all calls can be routed through the PBX, thus allowing the ability to review all records from a single source). The market is in flux with some vendors in betas or trials, others at varying stages of integrating their acquisitions, and still others in the first phases of FMC-PBX integration. One of the best offerings at the moment comes from Avaya. It has a strong market share in enterprise PBXs, owns its FMC system, has experience providing mobile extensions, and allows Avaya customers who arent satisfied to switch to other FMC players.