"We would like to have one main phone number and multiple phone lines for calling." Can a request like this to your phone company, be simpler than that?
You would be surprised to know how many different ways a phone company can set up your lines. And each solution has its own set of pros and cons.
Over-lines, hunt-groups, roll-over lines, pilot number, real number are the common terms here to be aware of.
Over-lines – There is one main number or pilot number which is the first line, and then there are over-lines or additional lines. Each line physically connected to your phone system to be able to provide you with multiple lines to dial out.
For example, if you need three lines coming into your office, then the request would be for one main number or pilot line and 2 over-lines or you can call it a one plus two over-line system.
If you need 4 lines coming in, then the request would be for 1 main or pilot line and 3 over-lines, ie one plus three over-line system.
Each of the over-lines are separate phone lines, with the same phone number attached to them ie your main or pilot phone number of your business.
The over-line system ensures that when your first line is busy, the next incoming call will ring on the next over-line, till all your lines are busy.
AND, more importantly, it will ensure that each of them will display your MAIN phone number as caller ID when you call out.
This is not the case with the hunt-group or multi-line system.