Apply Extension number to unlicensed Voice user

[DwightShrute]

I saw an article in a google search that says you can apply an extension number to a user without needing a voice license. The article did not explain how it could be done. I have run the typical powershell commands but they all fail, due to user not being licensed. Does anyone know if this can be done?

[#2]

@DwightShrute I would suggest that the article is wrong. 

'Extension Number' doesn't really have any meeting in Teams voice, everything is E164 anyway. Anyone in a call that involves a PSTN number needs a E5 or Teams Phone System license, other than conference calls.