I agree with Johnyreb totally.
Normally it's an alarm guy going to the telecom business. In my case, the alarm company owned their own monitoring station/paging company so it was a natural.

The insurance is what turns most people away from the business. There are also different levels of insurance as well depending on whether you do burg - risk factors eg. low, medium, high (drug stores, banks, electronic shops are high risk) and fire (high risk/insurance and requires licensing).
If you decide to get out of the security business down the road, and wish to maintain your existing customers, you need to keep the higher insurance unless you "sell" off your security customers to another company.

In summary, you can't afford to dabble in it. With the costs invovled, it's either go big or stay home. Hiring an experienced tech is a great idea. Take advantage of the panel manufacturers offering courses on the set up and programming of their systems as well.