Alarm Protocols

Pulse

• The Pulse format transmits digits by switching a carrier on and off, initializing the connection with a "handshake" and ending the session with a "kissoff." The rates and frequencies vary, and the signal is sent in a variety of formats, such as a 4/2 format, indicating that the pulse signal sends four digits for the customer's alarm account number and two digits that identify which zone the alarm is in.

Dual Tone Multi-Frequency

• Commonly known as touch-tone, Dual Tone Multi-Frequency, or DTMF, communicates through a telephone system with a distinctive pair of tones. Through a unique frequency, the tones represent a specific digit of a phone number. Once the alarm panel is programmed to send DTMF, the alarm receiver is dialed and receives a series of 16 tones over the telephone line. The DTMF protocol determines what the digits mean, and the monitoring company's software then interprets the signals.

FSK

• FSK, otherwise known as Frequency Shift Keying, converts data into specific frequencies for transmission to the alarm receiver at the monitoring company's site. Faster than Pulse, FSK also sends frequencies in a variety of formats, including 4/2, but also formats like 6/2/2, which is a six-digit account number, two-digit alarm type, and two-digit zone.

IP

• IP involves the transmission of alarms to the monitoring company on the Internet via User Datagram Protocol (UDP) and Transmission Control Protocol (TCP). Using broadband technology, data is sent over the network, then decoded by the alarm receiver at the monitoring company. With this format, a traditional phone line is unnecessary. However, homeowners should consider potential problems with disconnecting a phone line, which is an important backup in the event of signal or power failure.