Why is the connectionUri different in WSManConnectionInfo object for exchange and windows?

For exchange the connection uri used is : 

'http://machineName/powershell'

The WSManConnectionInfo object is created in the following way:


 WSManConnectionInfo connectionInfo = new WSManConnectionInfo(new Uri("http://machineName/powershell"), "http://schemas.microsoft.com/powershell/Microsoft.Exchange", ExchangeCredential)

To connect to windows, the uri used is 

'http://machineName::5985/wsman '

The WSManConnectionInfo object is created in the following way:
 WSManConnectionInfo connectionInfo = new WSManConnectionInfo(new Uri("http://machineName:5985/wsman"), "http://schemas.microsoft.com/powershell/Microsoft.PowerShell", credential);

Why is there a difference in the connection uri for exchange and windows?