December 22, 2011
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Comments
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Ken
Line seizure is a requirement of UL and NFPA72 and a properly wired RJ31X jack is required by telephone company tariffs as a STANDARD NETWORK INTERFACE (SNI) to connect an alarm panel to the switched telephone network.
The alarm is in SERIES with the telephone and as such DISCONNECTS ALL HOUSE PHONES on site when the alarm is triggered. (If the jack is not installed or installed properly, it is possible to BLOCK A DIALER by taking a phone off the hook or calling the premises and letting it ring. Without Line Seizure the alarm cannot HANG UP the phone and dial out. Thereby leaving the alarm dealer with an UNREPORTED event.
Proper wiring of the RJ31X is covered in the NTS Level 1 course , the Advanced course and the Fire Alarm Installation Methods course..
Joel Kent
FBN Security Co LLC
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Ken,
Thanks again for such informative new letters. I am in the process of changing my company policies and will be purchasing your contracts in the new year.
In the mean time, I would like to respond to the line seizure comments.
I have been in the security industry since 1985 and not one time have I come across a situation where line seizure is not possible. If you can get a dial tone from any location (and I assume the installer that wrote you does get it somehow) then it only takes a proper understanding of tip & ring and RJ31X jacks to properly redirect the phone lines to get line seizure. If, as he says, he finds himself in a situation where line seizure is truly not possible then he needs to sell the customer a cellular communicator.
In my opinion, not having proper line seizure would be a major concern. The installation manuals of security systems recommends proper line seizure. I would hate to have to go to court over this one.
Thanks,
Thomas M. Vordenbaum
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Hi Ken;
As for the problem with line seizure, I am attempting to wean all of my customers off the Ma Bell teat and get them over to GSM radios. Yes, it's more money, but it is 100% reliable. Never mind line seizure, what about VoIP not being 100% compatible with alarm communications? And about the only way to defeat it would be to wrap the house in Mylar. What should we do, go back to programming panels using Ademco Low Speed just to accommodate the phone company? I offer GSM at a discount rate to my customers just to make it enticing. I don't know about others in the industry, but about 80% of my service calls these days are related to my customers going off the POTS line and going VoIP. Plus there are no more cut phone line worries.
John from NJ
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Ken,
Line Seizure is required for Fire Alarm Systems employing Digital Alarm
Communicator Transmitters. The applicable code sections are;
2007 NFPA-72 Chapter 8 - Supervising Station Fire Alarm Systems
8.6.3.2.1.3 Requirements for DACTs.
(A) ADACT shall be configured so that when it is required to transmit a signal to the supervising station, it shall seize the telephone line (going off-hook) at the protected premises and disconnect an outgoing or incoming telephone call and prevent use of the telephone line for outgoing telephone calls until signal transmission has been completed. A DACT shall not be connected to a party line telephone facility.
2007 NFPA-72 Chapter 11 - Household Fire Alarm Systems
11.7.8 Supervising Stations.
11.7.8.1 Means to transmit alarm signals to a constantly attended, remote
monitoring location shall perform as described in Chapter 8 except as modified
by 11.7.8.1.1 through 11.7.8.1.3.
2010 NFPA-72 Chapter 26 - Supervising Station Fire Alarm Systems
26.6.3.2.1.3 Requirements for DACTs.
(A) ADACT shall be configured so that, when it is required to transmit a signal to the supervising station, it shall seize the telephone line (going off-hook) at the protected premises and disconnect an outgoing or incoming telephone call and prevent use of the telephone line for outgoing telephone calls until signal transmission has been completed. A DACT shall not be connected to a party line telephone facility.
2010 NFPA-72 Chapter 11 - Household Fire Alarm Systems
29.7.8 Supervising Stations. 29.7.8.1 Means to transmit alarm signals to a constantly attended, remote monitoring location shall perform as described in Chapter 26, except as modified by 29.7.8.1.1 through 29.7.8.1.4. 29.7.8.1.1 Where a digital alarm communicator transmitter (DACT) is used, the DACT serving the protected premises shall only require a single telephone line and shall only require a call to a single digital alarm communicator transmitter.
John Drucker, CET
Fire Protection Subcode Official
Fire/Building/Electrical Inspector
Fire Marshals Office
Borough of Red Bank, NJ
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Ken,
One question and/or comment always leads to another. Taylor brought up the line seizure issue. Even when companies obtain line seizure during the initial installation, you can bet that once there has been a change in telephone provider(s) and they have been to the home to rearrange the telco lines, your line seizure is a thing of the past. You will never know it until it becomes an issue. If you are lucky, you may find out during an unrelated service call when you send an test signal and there is no line seizure. Nature of the beast. At least when there is a law suit everyone gets invited to the picnic so get your invitation ready for the phone provider. Should be interesting as this trend expands since in most cases these companies are not licensed to touch alarm equipment to include the transmission line(s) and if they claim to be exempt from the licensing laws through a utility exemption, their subcontractors usually are not. I am sure we will see this surface at some point.
Bob Worthy CPP
President
Secur Technologies, Inc.