To enable a user for Microsoft Teams Direct Routing using PowerShell, you must configure their account with their specific phone number and enable them for Enterprise Voice. The Set-CsUser cmdlet is the correct tool for this task. It allows an administrator to set the essential -OnPremLineURI parameter to the user's E.164 phone number and the -EnterpriseVoiceEnabled parameter to $true. These settings configure the user's account to route calls via the on-premises Session Border Controller (SBC) defined in the Direct Routing configuration.

A. Set-CsCallingLineIdentity: This cmdlet is incorrect because it is used to create or modify Calling Line ID (Caller ID) policies, which control the phone number displayed on outgoing calls, not to enable a user for a specific voice routing method.
C. Set-CsOnlineVoiceUser: This cmdlet is incorrect for this specific task because it does not have the -OnPremLineURI parameter, which is required to assign a phone number for Direct Routing. It is typically used for other voice configurations.
D. Set-CsUserServicesPolicy: This cmdlet is incorrect as it is used to manage user services policies that control features like unified contact store, presence, and archiving, which are not directly related to enabling voice routing.

1. Microsoft Docs - Enable users for Direct Routing: This official documentation explicitly details the steps to enable a user for Direct Routing.

Reference: In the "Enable user and assign a phone number" section

the document states: "You can use the Set-CsUser cmdlet to configure the phone number and enable Enterprise Voice and voicemail for a user." It provides the following example command: Set-CsUser -Identity "[email protected]" -OnPremLineURI "tel:+14255550100" -EnterpriseVoiceEnabled $true -HostedVoiceMail $true.

Source: Microsoft

"Enable users for Direct Routing

" Microsoft Learn

learn.microsoft.com/en-us/microsoftteams/direct-routing-enable-users.

2. Microsoft Docs - Set-CsUser Cmdlet Reference: The official documentation for the Set-CsUser cmdlet lists and describes its parameters.

Reference: The parameter description for -OnPremLineURI specifies its use for assigning a phone number that is homed on-premises

which is the case for Direct Routing.

Source: Microsoft

"Set-CsUser

" Microsoft Learn

learn.microsoft.com/en-us/powershell/module/skype/set-csuser.

3. Microsoft Docs - Set-CsOnlineVoiceUser Cmdlet Reference: The documentation for this cmdlet shows its parameters

confirming the absence of -OnPremLineURI.

Reference: The parameter set for Set-CsOnlineVoiceUser includes -TelephoneNumber but not -OnPremLineURI

making it unsuitable for the primary step of enabling a user for Direct Routing.

Source: Microsoft

"Set-CsOnlineVoiceUser

" Microsoft Learn

learn.microsoft.com/en-us/powershell/module/skype/set-csonlinevoiceuser.