The possibility level provided by the telephone stations as well as mini - PBX, ceased to satisfy the needs of modern business. The emergence of Internet telephony and the development of the VoIP conception, which coincided in time with the rapid development of cloud services, led to the appearance of virtual (or logical) telephone stations, realizing at most the benefits of these technologies.

These methods are particularly effective in creating unified information systems of the distribution offices. Basically, any time one can create a workable communication structure for the company of any activity kind, employees of which are spread across the entire globe. In addition to that the client's single list of subscribers will look like an ordinary telephone directory. The subscriber network inner organization remains unknown to them.

Such system can replace not only the PBX, but also a call center. Its functions include:

• Subscriber's number distribution and routing of calls.
• Creating groups of subscribers
• Call queuing distribution
• Reporting.
• Managers' work monitoring.
• Automatic ringing around subscribers.
• Filling out forms.
• Organiziong subscriber's workplace.
• Implementation of voice menus.
• Integration with CRM.
• Recording messages.
• Team button.
• Call button.
• Multilateral conference communication.
• Conference communication with connected participants.
• Organization of the priority queue.

Virtual PBX benefits for the consumer are obvious. Above all, they are in the extension of switching possibilities , and consequently the increasing number of commercial transactions. At the same time the environment costs decrease rapidly as the main work is done by a powerful remote server. Its functioning reliability is ensured by databases and traffic duplication. Information security of such systems is provided by means of the information is transmittion via the communication channels encrypted and is decrypted directly in the subscriber's terminal equipment. Software is protected from viruses or Trojans of any type.

An important characteristic feature of the logical PBX is the ability to provide the operability connection of distributed subscribers in case of accidents in telephone networks. In this case, some of the functions are transferred to the local network. Even if this will reduce some of the full-fledged virtual PBX possibilitiesthe the system as a whole will remain operability and will quickly recover the lost data after the fault and function adequately.