Supporting remote workers has a history of being one of the more challenging tasks IT professionals are faced with. Over the years, a variety of solutions have been developed to grant off-site employees with remote access to internal applications, and each method has it's own strengths and drawbacks. Details aside, however, the overarching goals of each remote-access implementation are the same: reliability, security, and ease of use & administration.
VPN vs Cloud
Companies often use Virtual Private Network (VPN) solutions as a way to "extend the corporate network", allowing remote workers to access intranet applications as if they were on-site. The appeal of VPN based implementations is that no changes have to be made to the intranet application itself -- ideal when you have customized legacy applications that can't be modified or replaced with third-party solutions.
If, however, you have an application that can be replaced with a ready-made solution from a software as a service ("SaaS") vendor, then you may have an opportunity to reap multiple benefits in one fell swoop -- including easier access for remote workers. We experienced this at VoicePulse several years ago when we replaced the homegrown trouble ticketing system our Customer Service group was using with Salesforce.com. By moving that application "to the cloud", we drastically reduced the total cost of ownership of the application, while simultaneously answering the remote-access challenge. Because Salesforce is a browser-based software-as-a-service solution with no on-premise server, our employees can access it from anywhere as long as they have Internet access. Access is secured by the application login, accessing it remotely doesn't expose our internal network, and no VPN is needed.
What does this have to do with voice?
VPNs aren't a viable solution for your telephone system. Sure, we've seen IP phones that have built-in VPN clients. We've even experimented with low-cost VPN routers that allow IP phones to access on-premise PBXs, but both of those solutions are cumbersome. And most people are unwilling to go through the effort of starting up a VPN connection every time they need to make a phone call.
Hosted PBX services do for your phone system what Salesforce.com did for our ticketing system. You replace your on-premise phone gateway with one that's located "in the cloud". Your employees take home IP phones, plug them in, and get back to work -- as if they were sitting in your office. They can dial each other by extension, access their voicemail, and make & receive calls. All this without worrying about starting up a VPN. Your IT staff doesn't have to deal with poking holes in your firewall, and they can add and remove users remotely.
If the increased security and ease of administration wasn't enough to convince you, consider the fact that the cost savings can be as high as 40% when compared to the total cost of ownership of running your own PBX. Whether you have 2 or 20,000 employees, hosted PBX services are usually the most cost-efficient, easiest to manage, and secure solution for businesses.