There’s no need to complete any extra wiring in a building once internet connections are in place. Additionally, mobile apps and web browser-based phones can just as easily connect to the VoIP network as their desk phone and conference phone counterparts.
Set up Visual Voicemail. If your carrier supports Visual Voicemail, you can set it up with these steps: Go to the Phone app, then tap the Voicemail tab. Tap Set Up Now. Create a voicemail password, then tap Done. Enter your password again to confirm it, then tap Done. Select Custom or Default. If you choose Custom, you can record a new greeting.

This “Product Review” is a lot less helpful that is first appears. It amounts to little more that a list of providers, with no attempt to provide a feature-by-feature comparison, something that a “real” product review would provide. For example, which providers use a phone adapter (a la Vonage)? How many minutes do you get for the plan(s) mentions? Etc.
Callers aren’t going to spend time sitting through a menu that doesn’t let them, at the very least, leave a voicemail. If a caller knows their party’s extension number, an option can, and should, be “Press 1 to leave a voicemail,” or something along those lines. That way, clients can feel as if they’re expressing their concerns without needing to talk to an agent, and without the agent feeling sorry they couldn’t pick up while they were working on something else.