Communication credits and Pay-As-You-Go Calling Plans are both options for paying for phone usage in Microsoft Phone System.
Communication credits are a way to pay for phone usage on a pay-as-you-go basis. You can buy communication credits in advance, and then use them to pay for phone calls and other phone-related charges. Communication credits are deducted from your balance as you use them.
Pay-As-You-Go Calling Plans are a way to pay for phone usage on a monthly basis. You pay a fixed amount per user per month, and then you can make phone calls and use other phone-related features without worrying about running out of credit.
If you want to test the phone system without getting monthly calling plans, then you can use communication credits to pay for phone usage on a pay-as-you-go basis.
For toll-free numbers, you can purchase them separately and assign them to users as needed. If a user with a calling plan runs out of minutes, they can use communication credits to continue making calls. If you want to use pay-as-you-go for users with calling plans, then you will need to purchase an add-on license for each user.
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