Transmission method to supervising station
- Thread starter jkim780
- Start date
- Status
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Transmission method to supervising station
Reverse polarity is the oldest method. It uses a simple pair of wires between the location and the monitoring station, usually supplied be the TELCO. The equipment at the location puts a DC voltage on the pair with the polarity one way. When the equipment goes into alarm the polarity gets reversed which signals the monitoring equipment that there is an alarm. Since there is always a voltage present on the pair of one polarity or the other the line is supervised. If the pair is cut or shorted no voltage will appear it the monitoring equipment and a trouble condition will be initiated.
I'm not exactly sure what "DACT" means but I am sure it performs the function by sending digital information that would probably include more than just that there is an alarm.
Reverse polarity is the oldest method. It uses a simple pair of wires between the location and the monitoring station, usually supplied be the TELCO. The equipment at the location puts a DC voltage on the pair with the polarity one way. When the equipment goes into alarm the polarity gets reversed which signals the monitoring equipment that there is an alarm. Since there is always a voltage present on the pair of one polarity or the other the line is supervised. If the pair is cut or shorted no voltage will appear it the monitoring equipment and a trouble condition will be initiated.
I'm not exactly sure what "DACT" means but I am sure it performs the function by sending digital information that would probably include more than just that there is an alarm.
hbiss
EC, Westchester, New York NEC: 2014
- Location
- Hawthorne, New York NEC: 2014
- Occupation
- EC
Re: Transmission method to supervising station
A little research shows that "DACT" is really the familiar "digital dialer" we see all the time in alarm panels. No dedicated line necessary.
Digital Alarm Communicator Transmitter (DACT): A system component at the protected premises to which initiating devices or groups of devices are connected. The DACT will seize the connected telephone line, dial a preselected number to connect to a DACR, and transmit signals indicating a status change of the initiating device.
A little research shows that "DACT" is really the familiar "digital dialer" we see all the time in alarm panels. No dedicated line necessary.
Digital Alarm Communicator Transmitter (DACT): A system component at the protected premises to which initiating devices or groups of devices are connected. The DACT will seize the connected telephone line, dial a preselected number to connect to a DACR, and transmit signals indicating a status change of the initiating device.
- Status