Question : What Should the Title Be

Someone who does the following:

1.) All Corporate Networks, design, administration, implementation
2.) All Corporate Telephone System, Design and Impelementation
3.) Design, Implementation and administration of: Sharepoint, Office Communications Server, Exchange, Active Directory, Domain Controllers, DHCP Servers, DNS servers etc, etc etc

What is the appropriate title of such an individual?  Network Administrator doesnt seem to cut it

Answer : What Should the Title Be

Personally, I think "infrastructure" doesn't include the applications, but others may disagree.

I suppose you could go with IT Systems Engineer or Information Systems Engineer.