CID is faster than SIA because it sends what?

• A. It uses longer pulses.
• B. It sends a momentary tone instead of a string of pulses.
• C. It cannot send digits.
• D. It requires a dedicated channel.

Answer: (B)

Signaling speed comes from how the event data is encoded and sent. CID uses a compact, digital data burst that carries the entire event information in a single momentary tone, so the central station receives the message quickly. In contrast, the SIA format sends information as a sequence of tones that encode digits, which takes longer to transmit because more timing and transitions are required. So the faster method is the one that delivers the whole message in one brief burst rather than a longer series of tones. The other statements don’t fit: longer pulses would slow things down, CID can still send digits, and it does not necessarily require a dedicated channel.