My role is a field application engineer, (designing and validating proposed installations) but that also includes a variety of training (in person, remote and video based training), in-person support, phone support, etc. etc.
I've found that if the person providing the support has a lot of experience with the product, it will make the process much faster and easier. (Genuinely understanding vs. reading a script) So in your case, have your support guys install several systems. (actually install them, not just assemble them on a bench). Have them configure remote access, mount cameras, drill holes, and configure every feature so it will work reliably in a real-world setting.
On the phone, nothing ticks me off more than having to wait through a person reading a script. But real satisfaction with a call comes when the person you are speaking with LISTENS to you (instead of just going to the next step of the script), understands how the product works (and doesn't work) and can start to ask questions and diagnose based on the symptoms you are describing.
I agree with the other posting suggesting online chat. We don't really use it for support, but it's helpful sometimes for quick fix or simple issues. I've seen some online chat supports that even offer a menu where the user rates their competency, it ranges from "Novice: I know nothing about electronics" to "Tech Pro: speak to me like I'm a tech expert", this let's the support guy adjust his approach on a case by case basis.
I totally agree with the other suggestion of more benign hold music. Keep the music volume lower, this way when a human does come on the phone, it's obvious. If you must have messaging keep it low key, the support line is not the time to be trying to upsell someone who's ticked off that their existing product isn't working.
I've also found that having a resource that provides remote desktop support (TeamViewer is my favorite, but there are a number of other solutions) is invaluable. You are able to see exactly what the customer sees (if your product is PC based, or if it interfaces with a PC) and you can "drive" and show (as well as teach) the customer how to solve the issue. None of this "Do you see the red icon on the bottom right side of the screen?" 5 minutes later... "No, it sounds like you are clicking in the application window, I mean on the very bottom right of the screen..."
Teamviewer even allows you to brand a quick support version of their product with your company logo, so the customer see's that it's you, and, they don't have to go through installing anything. (run once, delete, and done).
In your case for example, if the customer needs help configuring the port forwarding on their router to remote view their cameras, then you are able to assist right then. Video looks "funny" on the screen, log into their remote viewer to see what it's looking like to diagnose what "funny" is... (Camera upside down? Something on the glass reflecting IR back? IR cut filter stuck? Now you know) It's not the end all solution, but it's a helpful tool to have in the box.