VoIP systems, sometimes called cloud PBXes, can manage all your voice communications from a central web console no matter how many extensions you've got, where your employees are located, or even what devices they're using. Most systems also offer features like video conferencing and team collaboration. Put all that together with subscription-based pricing that's generally much cheaper than an old-fashioned, on-premises PBX, and VoIP remains one of the best communications investments any business can make, especially during the pandemic.
But it can also handle other functions, including session setup (initiating a call at the target endpoint—the phone you're calling), presence management (giving an indicator of whether a user is "available," "away," etc.), location management (target registration), call monitoring, and more. Despite all that capability, SIP is simple compared to other VoIP protocols primarily because it's text-based and built on an easy request/response model that's similar in many ways to both HTTP and SMTP. Yet, it's still capable of handling the most complex operations performed by business-grade PBXes.

As mentioned above, alerting callers that they won’t be getting an immediate call back is of upmost importance for an entity’s reputation and a caller’s satisfaction.
In this world where leads are so fragile that they can go to your competitor if you don’t immediately answer their calls, managers must work hard to ensure that no qualified lead ends up in the hands of competitors. One way to curb volatile leads is by laying out a voicemail system. There is a boatload of free business voicemail tools that startups and mid-sized firms can configure to suit their specific demands.