You have an Exchange Server 2013 organization that is integrated with Microsoft Lync Server 2013. Users
report that they fail to make Unified Messaging (UM) calls.
You download the Unified Message Troubleshooting tool.
You need to perform an end-to-end test of the UM components.
Which cmdlet should you use?

A.
Test-ExchangeUMCallFlow

B.
Test-CsPhoneBootstrap

C.
Start-UMPhoneSession

D.
Test-UMConnectivity

Explanation:
Use the Test-ExchangeUMCallFlow cmdlet (the UM Troubleshooting Tool) to test call flow between Client
Access servers running the Microsoft Exchange Unified Messaging Call Router service, Mailbox servers
running the Microsoft Exchange Unified Messaging service, VoIP gateways, IP PBXs, Session Initiation
Protocol (SIP) servers and Microsoft Lync Server. The Test-ExchangeUMCallFlow cmdlet can be used to
diagnose configuration errors found in telephony components, Exchange 2010 SP1 or later or Exchange 2013
Unified Messaging settings, and connectivity issues between on-premises and hybrid Unified Messaging
deployments.
Incorrect answers:
Not B: The Test-CsPhoneBootstrap cmdlet verifies that a user can log on to Skype for Business Server 2015
using a Phone Edition-compatible device.
Not D: Use the Test-UMConnectivity cmdlet to test the operation of a Mailbox server computer running the
Microsoft Exchange Unified Messaging service.
Test-ExchangeUMCallFlow
https://technet.microsoft.com/en-us/library/ff630913%28v=exchg.150%29.aspx