Congrats on getting through the telephone stage. You should now be at the final stage which will consist of:
1. HR interview (45 mins to an hour) - they will discuss general type questions like, how do you deal with difficult clients/colleagues, etc. they will try and build a generalist picture of your prior background (a bit similar to last time) and will also sound you out regarding level and package.
2. SE (or SM) Interview. Normally this is with a Senior Exec, but if there are none available at the time a Senior Manager is asked to stand in. Again this is for about an hour, and is split into two elements:
a) Case Study - this is for them to gauge your thought processes and to see if you can absorb informaition quickly and produce high-level solutions to the situation at hand. Typically it will be around two companies merging, or a consolidation of client real estate and you have to talk through how you would manage it from not only a technical side, but from a business perspective also (think about staff retention, etc.)
b) This is the one on one chat with the SE/SM who may again ask some questions about your past, but the real point of this is for them to see how you handle yourself in one on one situations. Remember, the interviewer will be thinking throughout - 'Will this person fit well into Accenture/Network Technologies?' and 'Will this person resonate with the clients that I put them in front of?'
Best advice is to try to relax, and think that you have already sparked some interest otherwise you wouldn't have got through the first stage, so you have some prior skills/experience that they are actively looking for.