Discover the correct regex pattern to resolve Microsoft Teams Direct Routing dial plan translation issues causing failed user connections. Expert solution for MS-721 certification exam prep.
Table of Contents
Question
You have a Microsoft Teams Phone deployment that uses Direct Routing.
Users report that when they attempt to dial the following numbers they fail to connect.
- 321554223575
- 4669332728
- 5545454544
You have the following dial plan translation rule.
^([4-5]\d{7})$
You need to update the rule to address the issue.
How should you update the rule?
Select only one answer.
A. ^([3-5]\d{9,11})$
B. ^([345]\d{9-11})$
C. ^([3-5]\d{9-10})$
D. ^([345]\d{9,10})$
Answer
A. ^([3-5]\d{9,11})$
Explanation
The answer is ^([3-5]\d{9,11})$. ^([345]\d{9-11})$ does not work, as 9-11 will not catch all the numbers. ^([3-5]\d{9-10})$ does not work as 9-10 is not long enough. ^([345]\d{9,10})$ does not work as it is not long enough.
To resolve the issue where users cannot dial numbers like 321554223575, 4669332728, and 5545454544 in a Teams Direct Routing deployment, the existing dial plan translation rule ^([4-5]\d{7})$ must be updated.
Analysis of the Problem
Current Rule Flaws:
- The regex ^([4-5]\d{7})$ matches numbers starting with 4 or 5 followed by 7 digits (total 8 digits).
- The problematic numbers are 10–12 digits long and include a starting digit 3, which the rule excludes.
Failed Numbers:
- 321554223575 (12 digits, starts with 3)
- 4669332728 (10 digits, starts with 4)
- 5545454544 (10 digits, starts with 5)
Solution: Updated Regex
The correct regex must:
- Allow numbers starting with 3, 4, or 5.
- Accommodate 9–11 additional digits (total 10–12 digits).
Option A: ^([3-5]\d{9,11})$
- Matches numbers starting with 3, 4, or 5.
- Followed by 9–11 digits (total 10–12 digits).
- Covers all problematic numbers.
Why Other Options Fail:
- Option B/C: Invalid regex syntax ({9-11} instead of {9,11}).
- Option D: Allows only 9–10 digits (total 10–11 digits), excluding the 12-digit number.
The correct answer is A (^([3-5]\d{9,11})$). This regex expands the starting digits to 3-5 and adjusts the length to resolve connectivity issues for all reported numbers.
Implementation Steps
- Update the dial plan rule in Teams Admin Center.
- Test normalization using Test Number to confirm translations.
- Ensure no overlapping rules interfere with the new pattern.
By addressing both the starting digit range and number length, this fix ensures seamless call routing for Teams Direct Routing users.
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