What are the four types of alarm protocols?

• A. Pulse (4x2), Dual Tone Multi-Frequency (CID), SK (SIA), and IP
• B. Pulse, CID, SK, and IP
• C. Pulse (4x2), CID, SK, and UDP
• D. TDMA, FDMA, CSMA

Answer: (A)

Understanding alarm signaling protocols is about how an alarm panel communicates events to a monitoring station. The four main types you should know are Pulse (4x2), Contact ID (CID), SK (SIA), and IP. Pulse (4x2) is the older dial-based method that transmits coded pulse patterns over a telephone line. Contact ID is the widely used digital format that sends event types along with location details so responders understand what happened. SK, defined by the Security Industry Association, is another standardized protocol used by many panels and stations. IP uses the internet protocol to send alarm data over networks, enabling modern remote monitoring. The other options mix in concepts that aren’t alarm signaling protocols themselves—UDP is just a transport method used with IP, and TDMA/FDMA/CSMA are radio channel access methods rather than alarm event formats.