Understanding Teams Conference Calls

[mmaus0891]

Im trying to grasp how the audio conferencing works in Teams.

We have one test user that has the E5 license and now has the Audio Conferencing options on his account.  He has a 1-980-xxx-xxxx number listed as a default conference number.
1)  Im guessing this was created and assigned to our organization by Microsoft when the new license was purchased.  Is this correct?

His Conference ID is setup as Dynamic.
2) I have read that a single service can hold 250 attendees.  Since this the Conference ID is set to Dynamic...if I have another user with the E5 license...if both people start a meeting...im guessing Teams gives out the same 1-980-xxx-xxxx number for both people and supplies a different Conference ID number for each user to give out to attendees to use to login with...as long as the combination of both meetings does not go over 250 attendees...we should not have an issue.  Is this correct?

[#2]

@mmaus0891 Your E5 license includes the Audio Conferencing component, when this is assigned Teams will start providing dial in detail in their new meeting requests. The default number selected is based on the users location as defined in Teams, you can change it, often Teams doesn't guess well for every state in the US. By default these are Microsoft's default numbers, after you dial in you need to provide the conference ID to join the meeting. You can request additional numbers that might be in your same region code, then assign them as your users defaults. 

These numbers handle lots of customers, they have in effect limitless capacity. Each of your meetings could have 249 people dialed in at the same time in addition to the organizer.

[#3]

I guess this is the big question I am having an issue with is do I need to request more conference numbers?

My company is small. We have only about 30 users and I dont see more than 2-3 conference being held at a time and defiantly not having 250 in a conference at once.

Will this single line that Microsoft has given us be able to handle multiple conferences at a time via the different conference id codes? or do I need to have a separate phone number for each conference that might be happening at the same time?

[#4]

@mmaus0891 You don't request numbers, that's automatic.  You simply purchase licenses for each user, which your E5 licenses already include Audio Conferencing, so you're covered there.  All users in your organization will have the audio dial-in information in their Teams meetings provided.

The user's region/location controls which of Microsoft's numbers are provided in the Teams meeting invite, but all invites include a link to a page which lists all of Microsoft's PSTN dial-in numbers worldwide (https://dialin.teams.microsoft.com/) so attendees can select a different local number for themselves if they don't want to call the one shown in the invite.  This is all automatic and you don't have to do anything.

There are some caveats you'll want to be aware of when it comes to available minutes and charges for people dialing out to PSTN participants in meetings: 

https://docs.microsoft.com/en-us/microsoftteams/audio-conferencing-subscription-dial-out

[#5]

@Jeff_Schertz 

Im a little confused on the direction of the call in association to the minute pool.

The pool of minuted listed in the document are listed as "Dial Out From a Meeting\Call Me At" numbers...
Is this pool of minutes for people calling inbound to the 980 number Microsoft provided us (Which I would guess is the "Call Me At")...  or is this pool of minutes for users calling from the meeting out to other peoples phone numbers (Which I would guess is the "Dial Out From a Meeting")  ...or is the pool of numbers consumed no matter which way a call is made inbound or outbound?