Learn how to resolve call failures in Microsoft Teams Phone deployment by adjusting dial plan normalization rules. Discover the solution to ensure 9820 resolves to a full E.164 number.
Table of Contents
Question
You have a Microsoft Teams Phone deployment.
Users report that when they dial 9820, the call fails.
You have a dial plan that contains the following rules in order:
- NA-Emergency
- Pattern: ^9?(911|933)$
- Translation: $1
- NA-Service
- Pattern: ^9?([2-9]\d{2})$
- Translation: $1
- NA-Internal_User
- Pattern: ^(98\d{2})$
- Translation: +1330555$1
- NA-National
- Pattern: ^\D*9?1?([2-9]\d{2}[2-9]\d{6})$
- Translation: +1$1
You need to ensure that when a user dials 9820, the number is resolved to a full E.164 number for the United States.
What should you do?
Select only one answer.
A. Move NA-National above NA-Service in the dial plan.
B. Move NA-Service above NA-Emergency in the dial plan.
C. Set the pattern of NA-Internal_User to ^9(8\d{2})$ .
D. Set the pattern of NA-Service to ^([2-9]\d{2})$.
Answer
To resolve the issue where dialing “9820” fails in your Microsoft Teams Phone deployment, you need to adjust the normalization rule in the dial plan. The correct answer to the provided question is:
D. Set the pattern of NA-Service to ^([2-9]\d{2})$.
Explanation
The NA-Service rule is overriding the internal user rule due to its optional 9, so you must set the NA-Service rule to ^([2-9]\d{2})$.
Microsoft Teams uses dial plans with normalization rules to translate dialed numbers into standard formats, typically E.164, for proper routing and call handling. These rules are processed sequentially from top to bottom until a match is found.
Current Dial Plan Rules
NA-Emergency
- Pattern: ^9?(911|933)$
- Translation: $1
NA-Service
- Pattern: ^9?([2-9]\d{2})$
- Translation: $1
NA-Internal_User
- Pattern: ^(98\d{2})$
- Translation: +1330555$1
NA-National
- Pattern: ^\D*9?1?([2-9]\d{2}[2-9]\d{6})$
- Translation: +1$1
Issue Analysis
When a user dials “9820”:
- The system checks each rule in order.
- The number “9820” matches the pattern for NA-Service (^9?([2-9]\d{2})$), which captures only the first three digits (e.g., “982”) and translates it as $1. This results in an incomplete number, causing the call to fail.
Solution
To fix this:
- Modify the pattern of NA-Service to ^([2-9]\d{2})$. This ensures that only three-digit numbers (area codes) are matched by this rule.
- With this adjustment, “9820” will no longer match NA-Service and will proceed to the next rule, NA-Internal_User, which correctly matches and translates it into a full E.164 number (+13305559820).
Why Not Other Options?
A. Move NA-National above NA-Service
This would not resolve the issue because “9820” does not match the pattern for NA-National (^\D*9?1?([2-9]\d{2}[2-9]\d{6})$), which expects a 10-digit number.
B. Move NA-Service above NA-Emergency
Changing the order does not address the root cause of the issue—an incorrect pattern in NA-Service.
C. Set the pattern of NA-Internal_User to ^9(8\d{2})$
This would break normalization for other internal numbers starting with “98,” as it introduces an unnecessary leading “9.”
Key Takeaways
- Normalization rules must be precise and ordered correctly to avoid conflicts.
- Testing dial plans using tools like the Dial Plan Tester in the Teams admin center is essential for verifying changes.
- Always aim for patterns that capture only intended numbers while leaving others unaffected.
By implementing option D, you ensure that “9820” is resolved correctly without disrupting other dialing scenarios within your organization’s Microsoft Teams Phone system.
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