10.1 Digital Alarm Communicators and Legacy Phone Paths

Why eight hours of transmission sit on a closed-book exam

The New York Department of State (DOS) Security or Fire Alarm Installer written exam lists alarm transmissions among the bulletin topics. In the 81-hour qualifying course, that subject is Module 2, Control Panels and Alarm Transmissions. 19 NYCRR 196.8 Module 2, subject III, is ALARM TRANSMISSION for 8 classroom hours — more classroom time than Module 2 spends on control devices (6 hours) or job planning (1 hour). Independent OpenExamPrep study material that helps candidates prepare for this exam treats those hours as the off-premises path: how a fire alarm control unit (FACU) or security control gets a signal out of the building to a central station. This section is not a manufacturer programming manual and does not claim DOS or National Fire Protection Association (NFPA) review.

A detector that alarms locally and never reports is a local system. The license still covers that work. The exam, the 8-hour block, and almost every commercial fire specification expect you to name the communicator, the path, and the receiver. Module 2.III is not fire-only. General Business Law (GBL) Article 6-D licenses security or fire alarm work. A burglar communicator and a fire communicator share the same handshake vocabulary even when the codes, listings, and supervision times differ.

The sitting is closed-book. You will not be handed an RJ31X pinout or an NFPA 72 excerpt. You must picture seize-line, handshake, kissoff, and Contact ID from memory, and you must refuse the story that New York published a single date after which every analog fire path is illegal.

DACT and DACR — two boxes, one conversation

A digital alarm communicator transmitter (DACT) lives at the protected premises. It is the dialer: a board in the FACU, a module on the FACU, or a listed communicator cabinet that the FACU trips. When the control has an alarm, supervisory, trouble, or restore to send, the DACT goes off-hook, seizes the telephone line, dials the supervising station, and sends a digital (tone) message.

A digital alarm communicator receiver (DACR) lives at the supervising station (the central station in 19 NYCRR 195.1(b) language — Section 10.3). It answers the call, proves it is a fire/security receiver by sending handshake tones, records the message, and sends kissoff (acknowledgment) so the DACT can hang up.

If you reverse the letters on the exam, you reverse the building. The transmitter is in the occupancy. The receiver is off-premises. Ownership of the transmitter does not change that map: 195.1(b) says the transmission equipment for the subscriber’s protected premises may be owned by the central station, the subscriber, or any other person.

Historical dual analog lines

For decades the default fire DACT layout was two analog telephone lines — plain old telephone service (POTS) copper — at the protected premises. The teaching story was simple:

• Line 1 is the primary path.
• Line 2 is the secondary path.
• A single cut, storm, or telco hit must not silence both means at once.
• Each line is supervised so a dead pair shows trouble at the premises and is reported to the DACR.
• The DACT is programmed with two receiver numbers (or a primary and a backup) so a failed sequence on the first number tries the second.

That layout still appears on existing systems and still appears as a distractor. It is not automatically the only lawful 2026 fire path. Later NFPA 72 teaching (commonly cited from the 2013 edition onward) expects a DACT to use one telephone line (number) plus another transmission means — performance-based IP or cellular, one-way radio, or two-way radio — rather than two analog pairs as the default. A second telephone line is commonly taught as permitted only when those other technologies are not available at the premises and the AHJ approves the two-line arrangement, with the DACT programmed to call a second DACR number if the first sequence fails, and with each telephone means tested.

Do not memorize a New York-only exception that “DOS still requires two copper pairs.” DOS licenses the installer. The AHJ and the adopted NFPA 72 edition decide whether a given path is acceptable on that occupancy. The July–December 2026 bulletin says code questions are based on the New York State Uniform Fire Prevention and Building Code and NFPA standards; it does not print edition years. The 2025 Uniform Code, effective December 31, 2025, references NFPA 72—22 for work under that code. Chapter 4 already taught that two-clock problem. Use it here: bulletin language versus currently adopted reference.

Seize-line, RJ31X, and why the house phones go dead

Line seizure is the DACT’s first job. Commonly taught NFPA 72 DACT language: when the DACT must transmit, it shall seize the telephone line (go off-hook) at the protected premises, disconnect an outgoing or incoming telephone call, and prevent use of the line for outgoing calls until transmission is complete. A DACT shall not be connected to a party-line telephone facility.

The field jack you will still see is the RJ31X (an 8-position jack wired so the DACT sits ahead of the premises phones). In standby, the shorting plug or the DACT’s idle contacts keep the house phones in series with the telco pair. In alarm, the DACT breaks that series path, takes the pair for itself, and the phones on the desk go silent until kissoff and hang-up. That is not a defect. That is seizure working.

Installer traps:

• Landing the DACT on a downstream house jack so a receptionist can stay on the line and block the fire signal.
• Using a consumer splitter instead of an RJ31X so seizure never disconnects the phones.
• Sharing a line with a fax, credit-card terminal, or DSL filter that will not release.
• Calling voice over IP (VoIP) from a cable modem “a phone line” because the analog adapter has an RJ11. Seizure, loop current, polarity, and dual-tone multi-frequency (DTMF) often fail on consumer VoIP even when a person can still talk.

A managed facilities-based voice network (MFVN) is the commonly taught NFPA 72 name for a carrier-managed analog-equivalent voice path that a DACT is allowed to treat as a telephone line. A kitchen-grade analog telephone adapter is not automatically an MFVN.

Handshake, kissoff, and the retry loop

Treat the call as a script. If any step fails, the DACT does not “hope.” It retries.

Handshake is the receiver identifying itself as ready. Kissoff is the receiver saying the message was received. Candidates mix them. Handshake is before the data. Kissoff is after the data. A DACT that hears handshake, dumps Contact ID, and never hears kissoff has not completed the transmission.

Commonly taught NFPA 72 DACT retry (label these as commonly taught NFPA 72 communicator figures, not as unique New York minutes): each transmission attempt is limited (often taught as not more than 90 seconds); if the first attempt fails, the DACT resets and retries; a small number of attempts is allowed (often taught as 5 to 10); if all attempts fail, the premises must indicate failure to communicate. Do not invent a DOS-only 90-second New York rule. The 90-second figure, when you cite it, is DACT attempt timing in NFPA 72 teaching — not the time a central-station operator has to call the fire department, and not a statewide DOS stopwatch.

Line-fault indication on a DACT telephone means is commonly taught as a few minutes at the protected premises (older DACT language is often taught as about four minutes) so a two-second telco hit does not nuisance-trouble the FACU. Again: that is commonly taught NFPA 72 DACT supervision, not a unique New York minute.

Formats — Contact ID as commonly taught

The DACT and the DACR must speak the same format. Independent OpenExamPrep teaching for this exam uses Ademco Contact ID (SIA Contact ID) as the commonly taught format because it is what most New York central stations still expect on analog and on many IP/cellular translators.

Contact ID is DTMF. A commonly taught frame is:

• CCCC — subscriber account number (four digits on many panels; some accounts use more digits in extended formats).
• Q — event qualifier: commonly taught 1 = new event, 3 = restore (some documentation writes E/R instead of 1/3).
• EEE — three-digit event code.
• GG — group or partition (often 00 on a non-partitioned panel).
• ZZZ — zone or user number.

Event codes you should recognize as commonly taught Contact ID, not as a New York statute:

Older 4+2, pulse, and other SIA formats still exist. If the exam names Contact ID, answer with account + qualifier + event + zone. If it names “the analog dialer format,” Contact ID is the safe commonly taught answer. Do not spend the sitting inventing a New York-only code list.

Automatic test timers are licensed programming

A DACT that never sends a test can be dead for a week while the FACU looks normal. Historically, fire DACTs automatically initiated a test signal to the DACR at least once every 24 hours. Later NFPA 72 DACT teaching commonly uses more frequent path tests (often taught as 6-hour tests of telephone means when two telephone paths are used). Burglar communicators still often use a 24-hour test timer under security listing practice. Do not paste the burglar timer onto a fire single-path IP communicator (Section 10.2).

Programming the account number, the primary and backup receiver numbers, the format, the test interval, and the failure-to-test / fail-to-communicate response is programming the client’s control panel and communication equipment. 19 NYCRR 195.1 includes communication equipment in installation, and it includes programming or reprogramming for access codes, system protocol, bypass features, and hours of operation. Account numbers and test timers are system protocol. The same acts are servicing when you repair a failed communicator. Doing that work from a laptop in the shop does not make it unlicensed: 195.1(f) treats off-site participation, and knowledge of on-line/off-line condition and protocol, as assisting.

POTS sunset — no New York-wide ban date

Carriers are retiring analog copper. That is a telephone-industry fact, not a DOS bulletin date. Many AHJs no longer accept a single analog line as the sole fire path because the pair is unsupervised in the modern network, because VoIP substitutes fail seizure and DTMF, or because later NFPA 72 editions already pushed DACTs toward a second, non-telephone technology.

Independent OpenExamPrep teaching for this exam is explicit:

• Do not invent a statewide date on which analog fire communicators became illegal in New York.
• Do not claim the DOS exam bulletin lists a POTS sunset.
• Do not claim every VoIP adapter is an MFVN.
• Do teach that the AHJ and the adopted NFPA 72 edition govern which paths are permitted on that building.
• Do teach that a listed IP or cellular communicator (Section 10.2) is how most 2026 fire jobs leave the copper era.

Exam traps

• Calling handshake and kissoff the same tone.
• Wiring the DACT after the house phones so seizure cannot drop a busy line.
• Treating consumer VoIP as a listed analog fire path.
• Reciting a fake New York analog-ban date.
• Treating two analog lines as the only remaining legal fire layout after 2013-era NFPA 72 teaching.
• Leaving test timers and account numbers to an unlicensed “monitoring clerk” as if 195.1 stopped at the keypad.

When you can seize, handshake, kissoff, name Contact ID, and refuse a fictional statewide copper ban, you have the analog half of Module 2.III. Section 10.2 is the IP and cellular half.