A discussion of integrating life safety and BAS isn't complete without mentioning the type of protocol to use. Most commercial fire alarm systems have developed proprietary communication protocols for external communications. However, many BAS utilize open protocols, so the system designer needs to decide which protocol to use. As can be expected, either option presents pros and cons.
Building drivers for proprietary protocols can be expensive, and since each one is unique, it can only be used with the system for which it was developed. On the other hand, since proprietary drivers are developed for a specific system, they tend to be perfectly suited for use with that system and provide the full range of functionality available.