turboDial with Twilio is a “Voice Over Internet” (VOIP) service and takes full advantage of the capabilities of Internet based connections and routing.
For that reason, the basic answer to the question is: You need zero phone lines. You simply need a good Internet connection.
If you have many users in your team sharing the same Internet connection, they can all be simultaneously making and receiving calls with turboDial. The only constraint is that the speed capacity of your Internet connection needs to be higher to accommodate many users.
In place of the question posed in the article title, two other questions are more relevant:
- How many Caller ID Numbers do I need?
- How many Inbound Numbers do I need?
The answers to these questions depend on how you have organized your business.
Caller ID Numbers: you need at least one Caller ID number, and all of your turboDial users can share that Caller ID as they are making outbound calls. Your contacts will often call you back at the Caller ID number since they see it in their phone history, so you want your Caller ID number(s) to be for phones you can answer in your business.
Inbound Numbers: Some turboDial customers continue using their current phone service for receiving inbound calls, and in some cases that can even be your mobile phones. For that reason you may not need any Inbound Numbers. However, if you will be using SMS in turboDial then you are required to have at least 1 Inbound Number. And if you want to track your inbound calls in Infusionsoft then you should obtain Inbound Numbers for each function (or person) in your business that needs to be independently reachable by callers. Your Inbound Numbers can also be used as Caller ID numbers.