While I agree with the intent of the prior posts, only 10% of any ISO rating is associated with the receiving and handling of fire alarms. At absolute *worst* case a 0% credit of this section results in a single classification change (i.e. ISO 5 to ISO 6), which in most cases is statistically marginal to property insurance costs.
At the core, ISO is concerned about maintenance and ownership. Using your own transmitters and systems (that are routinely tested, have alarming system, have backup systems, etc., etc.) could help you get closer to full credit in that sub-section (max 5% points) while relying on other's systems, such as SMS generally gains you zero credit since your department is not in control of the system (i.e. there is no guarantee that your emergency message will get through in a timely manner). Even contracts with paging companies that have Service Level Agreements don't qualify.
Without spending too much time on the soapbox, this really has a big impact for those departments that are considering all digital radio systems. The traditional two-tone voice pagers are not yet digital-able so many are (barely) maintaining a legacy system just for paging or going to alpha pagers off of a contracted system and losing available ISO credit.
I'm a big advocate of understanding ISO and what it means to raw dollar costs to your community and your community partners. Spending time to understand your rating, the actual FSRS (and the new proposed one), requesting new periodic audits (and learning from them) and using Fire Chiefs Online to assist in your pre-planning are worthwhile endeavors that can completely change how your community views your FD.
/Jeff