USE of the Programmable Relay, Doorbell Function

Rev. A.2, 10/03

Page-17

To return the red/green LED logic to factory set default, put the unit into program mode and enter 7-4.

6. USE OF THE PROGRAMMABLE RELAY

The DK-26 CPU board includes a second relay whose 5 Amp, SPDT contacts are marked CX, NCX and NOX (see Figure 2). This relay is employed for different functions which are selected by commands sent to the CPU board while the unit is in program mode. In general, you need to choose the function you want to make active for this relay (if any) and the following sections lay out the choices.

6.1 DOORBELL FUNCTION

As delivered, the programmable relay will operate when the Bell key is pressed when the unit is in “normal” operating mode (ready to accept a code). The Bell key is used a great deal in programming operations but the relay will not operate during programming (including initiating and exiting programming mode).

The purpose for this is to operate a real doorbell so that unauthorized
persons outside the controlled door can request entry. Most	CX	NOX
commercial doorbells are furnished with their own power supply, so	CX	NOX

typical wiring is as shown in the drawing to the right.

Note that if you don’t plan to use this function, a blank rectangular label is supplied which can be used to cover the “BELL” legend on the keypad face. This avoids misleading a person on the outside of the door.

6.2 DURESS FUNCTION

DOORBELL POWER SUPPLY

The duress function is used for high security applications. It allows a person being threatened to release the door but simultaneously create a silent alarm which would be employed to summon assistance. To make this work, obviously the threatened authorized person has to enter something different than a standard User code.

The DK-26 handles this requirement by establishing the Hard code as a duress code. You need to do several things however to implement this.

Ordinary operation must be via one or more User codes (see Section 4.2 for programming)

Program the Hard code as your duress code (see Section 4.1).

Put the unit in program mode , and enter 7-5. You will see the two flash confirmation. Exit program mode by pressing the Bell key or waiting 30 seconds.

Now, when you enter a user code, the door will open but when you enter the Hard code, the door will open and the programmable relay will switch. The door will remain open for the amount of time programmed but the programmable relay will stay switched (it latches) until the hard code is entered a second time to reset it. Use the programmable relay contacts (CX, NOX and NCX) to report the releasing of the door under duress. This can be done by interfacing with an alarm panel or dialer. Note that a duress code is rarely used. To make the code easier to remember, you can select a Hard code that is close to the User code (if only one User code is being employed) or you can select a short hard code. Note finally that selection of this option means you give up the opportunity to implement a doorbell or other use of the programmable relay.