In signaling formats, which statement correctly identifies the slowest and fastest formats?

• A. Slowest CID; Fastest 4x2
• B. Slowest SIA; Fastest CID
• C. Slowest 4x2; Fastest CID (Touchtone)
• D. Slowest 4x2; Fastest DTMF

Answer: (C)

Signaling formats differ in how efficiently they encode and send event data over a telephone line, so some formats take longer to transmit than others. The older 4x2 format is slower because it uses more digits and a more verbose signaling pattern, which means each alarm event takes longer to convey. Contact ID (CID) is designed for quick, concise event communication, and when CID is sent using touchtone (DTMF) signaling, the tones carry the data rapidly to the central system. SIA, while reliable and capable of carrying detailed information, tends to be less compact than CID, so it isn’t as fast as CID in this comparison. Therefore, the slowest format is 4x2, and the fastest is CID transmitted via touchtone.