Configure bulk Exchange 2013 servers for Unified Messaging and Unified Messaging Call Router Settings.
Set the UMService and UMCallRouterSettings for the servers:
Get-UMService | where {$_.identity -like ‘MBXSVR*’} | Set-UMService -DialPlans dialplan1 -UMStartupMode “dual”
Get-UMCallRouterSettings | where {$_.identity -like ‘MBXSVR*’} | Set-UMCallRouterSettings -DialPlans dialplan1 -UMStartupMode “dual”
Configure the Exchange Certificate for the UM and UMCallRouter srevices.
Get-ExchangeCertificate -Thumbprint <thumbprint of Certificate> | Enable-ExchangeCertificate -services UM, UMCAllRouter,IIS
Restart the following Services on each server:
MSExchangeUM, MSExchangeUMCR
Ex-Shell 