Do you have monitoring systems for heating, cooling, water pressure, high water levels? Processes that are normally checked by the security or safety groups on a regular basis? Add them into your mix. Think about what you want. Do you want a visual image to appear if something goes out of sync? Do you want a data stream to appear in that image? Do you want a specific physical response? Like I said, this is the easy part. It will require you to push yourself into forward, imaginative thinking, but it is easy. Give yourself the mental attitude that everything is possible ... and then go buy some duct tape.
Step 2: Investigate. If you are working from scratch, this part, although potentially a bit complicated and involved, is still easier than if you are adding in or planning an upgrade. Why? Because everything that you look at from scratch is new technology and therefore stands a better chance of being compatible. If you are working with older technology, you may not find the bells and whistles that you require to make things tick. Technically, you will choose one system to use as your main focus point. Let's say CCTV. This is now the point where all information from all systems will come together as a single response center.
Next, you lay out your controlling system with all the bells and whistles that you want in place and then shop around for the perfect CCTV controller to handle it. Once done, you move to your access control system. Again, you add all of your bells and whistles, but now, before you can settle on an actual system, you must verify that the outputs of that system will match your input requirements of the CCTV system. This is easy if all you are doing is triggering an event from a contact closure, i.e., a card is presented and a trigger calls up a camera to record. However, if you want a data stream to appear on the screen (i.e. card number, name, time, date, etc.) and you want this to be recorded into the video reference, you have a challenge.
Equally, if you want other functions you may need to shop around to find an access system that; 1) outputs data and 2) will interface in a language that your CCTV system can interpret. There are no set standards that say all systems will output in a single data language. It is very possible that at this first junction you may find that you will have to change your CCTV controller to match or handle your access controller.
You then repeat this process with your alarm system, and any/all other controlling or reporting functions throughout. The bad news is that you will most likely come up short with your communications interfacing. Coming up with two systems, say CCTV and access control that can talk together and work in a functional process of trigger and respond is fairly easy. Getting three, four or even 10 systems (new or old) to interact together is another story. This is the joy of working with multiple formats from independent industries, especially if you are trying to tie existing, older equipment with newer, innovative ideas. If you mix outdated technology with new technology, there's a good chance you will find yourself up against the proverbial wall. However, there is hope if you will come out of the box and look around.
Our modern culmination dilemmas are being approached and solved by a whole new breed of manufacturers. These are the "solution" products. Companies such as DVTel with their iSOC (Intelligent Security Operation Center) and GE with their Facility Commander are working to solve your whole system culmination problems. These are the products that are giving everyone equal ground on being able to offer, design and produce full-scale integrated systems.
For me to tell you that this process is easy would be a discredit to the process itself. You will still need to investigate each point of your process. You will still need to layout the triggers and desired responses. The beauty of it is that these manufacturers of solutions know their stuff and are able to assist you with your design without costing you a penny. My best suggestion is that when you start your job, you are up-front with your client and you get busy calling the experts. Yes, you should still have a pretty good idea what you want to accomplish. You should still have your interaction plan worked out. But you should also keep your mind open to suggestion and ideas.