Hardwired smoke alarms (i.e., hardwired to home power) aren’t supposed to integrate with a home security system, and I think that most building/fire codes specifically prohibit that. That’s not to say that it can’t technically be done, but it shouldn’t.
For a “traditional” alarm system, the basic components are a control panel, an enclosure for that panel, a wall-wart transformer, a backup battery, one or more keypads, one or more sirens, and any sensors you’d want to use (door/window contacts, glass-break sensors, motion detectors, smoke/heat detectors, etc.). Most control panels have a dialer built in to call a central station over a POTS line. If you want to use wireless devices, you’ll need to add a wireless receiver.
[ul][li]The control panel is the “brain” of your system, and everything connects to it. It’s mounted inside a metal enclosure which should be somewhat hidden, and some distance away from the entry door(s). A burglar shouldn’t be able to easily find it, or he could destroy or disable the alarm before it sent a signal to the monitoring company.[/li]
[li]Alarms are designed to have battery backups that will last for several (preferably 24+) hours. These also mount inside the metal enclosure.[/li][/ul]
Often alarms are sold as kits, with additional sensors and devices available to meet your particular needs. Here’s an example of a kit which would go a long way toward getting you started:
http://www.homesecuritystore.com/p-1734-ultimate-power5-kit32-power5-dsc-power-1832-ultimate-security-bundle.aspx
It includes all the items I mentioned above, plus 3 wireless door/window sensors, 1 wired motion detector, and 1 wireless keyfob (so you can arm/disarm your system remotely, without using the keypad). To it I’d recommend adding a PK5500 keypad, which sells on that website for $97. That keypad has an alphanumeric LCD, which will make programming much easier. You would also add whatever other wired or wireless sensors you wanted to use–wired sensors can be of any brand, but wireless would need to be DSC.
If you wanted to control (arm/disarm, get text message notifications, etc.) the system through Vera, you would need to add an IT100 card, which would mount inside the enclosure with the control panel; it costs about $65.
If you have broadband internet at your home (and if you don’t, you won’t be able to effectively use Vera to control the system anyway), you can use VOIP for alarm monitoring, and you don’t need a cellular communicator.
I don’t really know anything about the Visonic system, though it looks like the control panel and keypad are all in the same box. This isn’t the best arrangement, as a burglar could easily just smash the system to disable it. I don’t recall hearing of a Vera plugin that would work with that system, either.
Setting up an alarm system isn’t especially difficult, but there are a lot of parts involved to do a good job of it. Again, I’d recommend a lot of reading at diyalarmforum.com to get started.