Hosted PBX
Weaknesses of a Hosted PBX
The best hosted PBX services offer almost all of the features and benefits of premise-based PBX systems. Some things, however, are hard to offer in a hosted environment, and only the best services offer these functions. Features that fall into this category include real Automatic Call Distribution (ACD) instead of simple hunt groups, flexible company directories, call transfers between extensions (or to an operator or an ACD queue), and real-time system monitoring.
Some functions of premises equipment are hard for any hosted system, such as sharing a limited number of business phone lines among a larger number of users. In a hosted system, each user needs to have a separate line. As mentioned elsewhere, the high call capacity and scalability of a hosted system usually offset this drawback. Hosted users can take many more calls than the limited number of lines in a hardware PBX would allow, and they only have to pay for what they use instead of either over-spending or under-providing for their needs. The promise of hosted PBX services offered through VoIP technology will further reduce this problem by providing phones "lines" through the internet.
The last important weakness for a hosted PBX service deals with dialing between extensions. With a hardware PBX, employees can usually dial each other without going out onto the telephone network. These systems offer an "intercom" type function that connects users to each other. In a hosted system, the users may be anywhere, in or out of the office. Placing a call to another company employee means dialing their number directly or dialing into the hosted service and selecting their extension, because the PBX is out on the PSTN, not inside the building. In some hosted PBX services, this drawback has also resulted in an inability to transfer calls between extensions, but better hosted systems have solved that problem.