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Multiple Guard Unit Call Using MDS Sensors Decoder

September 7, 2017

There are many installations with two or three MDS Digital Guard Units. If tenants want to use a different button to call each MDS Guard Unit, it is possible using an MDS Sensors Decoder.

There are many installations with two or three MDS Digital Guard Units. If tenants want to use a different button to call each MDS Guard Unit, it is possible using an MDS Sensors Decoder.

Required material & software:


It is mandatory to use LOFT Extra Telephones with 3 buttons. Each button will call a different MDS Digital Guard Unit. 

Door Open Button (blue) will always call the Main MDS Digital Guard Unit. F1 and F2 buttons will be configured to call the other two Guard Units.

F1 and F2 buttons of each telephone will be connected to one port of the Sensors Decoder 2429 (Group 0 and Group 1).

Cables form F1 and F2 should be connected to terminal “S” on the Sensors Decoder port. Negative port (“-“) is not needed to be connected.

Two Guard Units will be connected to the Accesses shifter 2379 and the other one directly to the MDS Digital Guard Unit.

Decoder Bus will start from the MDS Central Unit and will connect all the Audio Decoders 2424 and the Sensors Decoder 2429.

In order to have the same reference level, the negative terminal from al the power supplies on the installation, should be joined.

Guard Units Ref.2537 Configuration:

After installing all the devices and cabling process is finished, Guard Units address and mode have to be configured.

       1. ADDRESS:

The Guard Unit has a number assigned, which must correspond to the number of the MDS switcher where it is physically connected. (0...9).

In this particular case, Guard Units will be configured as 1 (main), 2 (for F1) and 3 (for F2).           

To change this number, which is 0 by default, keep the # key pressed until a question mark appears on the display. Enter the number of the desired Guard Unit, to which the system will respond with OK.

Once the Guard Unit number has been changed, the system must be rebooted so that the MDS Central Unit can recognize it.

      2. MODE:

Guard Units should be configured as Day Mode. Proceed first with Guard Unit 3, then Guard Unit 2 and finally Guard Unit 1.

How to select DAY MODE:

  1. Press "0".
  2. The display will show a series of dashes. Enter "A" followed by "3" repeatedly until the dashes.
  3. The display presents the current MODE. Use the arrow keys to select the DAY MODE.
  4. Press “B” to validate.

In Guard Unit number 1 will appear an “R” on the display. It means this Guard Unit will receive the calls when somebody press the Door Open Button in one Loft Extra Telephone.

Audio Decoder Ref.2424 Configuration:

Once the Guard Units are configured, it is time to program the Audio Decoder. It can be done using one of the Guard Units of the system. This is the procedure:

  1. Make sure system is not busy and press "0".

 The display will show a series of dashes, depending on the User Code Length programmed into the system.

  1. Enter the "Access Code":

        AB21AB: if display shows 6 dashes.

        AB21A: if display shows 5 dashes.

        AB21: if display shows 4 dashes.

  1. Enter the Program Code:

The default value is 19025.When the code is entered correctly, the system goes to "Main Menu." If a wrong code is entered, the "Access Code" must be entered again.

  1. Main Menu: 2 – Decoders.

Use this option to program the number assigned to each one of the telephones linked to the audio decoders installed in the system.

  1. 2 - Decoders: 1- Individual Programming:
  • System asks us to press the PGM on the decoder:

          The systems asks you to press the decoder' "programming button."

  • Press the programming button of the decoder to be programmed

           Use a small screwdriver to press the programming button.

  • Enter the code numbers. The system will ask for the code number to be assigned to each of the phones that will be connected to its outputs.

           Telephone 1: 0101

           Telephone 2: 0102

           Telephone 3: 0103

           Telephone 4: 0104

  • Confirm data. Every time you enter a code you must use the "B" key to confirm. Once this is confirmed, the system will ask for the code for the next telephone.

Sensors Decoder Ref.2429 Configuration:

Sensors Decoder have to be programed using the same procedure as the audio decoders (Steps 1 to 4). The only difference is the codes to be assigned to each sensor (Step 5).

In this particular case, the codes will be:


  • Sensor 5: 001 à F1 from Telephone 0101.
  • Sensor 6: 002 à F1 from Telephone 0102.
  • Sensor 7: 003 à F1 from Telephone 0103.
  • Sensor 8: 004 à F1 from Telephone 0104.


  • Sensor 1: 101 à F2 from Telephone 0101.
  • Sensor 2: 102 à F2 from Telephone 0102.
  • Sensor 3: 103 à F2 from Telephone 0103.
  • Sensor 4: 104 à F2 from Telephone 0104.

Following this configuration, Sensor Group 0 will be used to call Guard Unit 2 and Sensor Group 1 to call Guard unit 3.

Wincom+ Configuration:

The last step is to proceed with the Wincom+ Configuration.

  1. Connect the Central Unit 2405 to the PC using the USB to RS485 adaptor 24661.

  2. Check the USB to RS485 COM Port on DEVICE MANAGER Page on Windows.
  3. Create a new installation.
  4. Add a New Block and insert the Central Unit with Address “0” (Default Factory Configuration. Check Address Dipswitches).

  5. Select the present elements in the installation. In this particular case, Apartments, Guard Units and Sensors will be selected.

  6. After Installation is created, go to FXL Net Menu and click on Serial Port. Select the COM port of the USB to RS485 that appears on DEVICE MANAGER Page.
  1. Click on Guard Units on the Left Menu. After that, double click on the blank window. Add the 3 Guard Units (Tab key to add).

  2. Click on Sensors on the Left Menu. Double click on the blank window. Create a new Sensor Group on “Call to Extra Guard”.
  1. Enter the Number and Description.
  2. Select the Guard Unit à Additional Guard Unit. Indicate in the box the number of the extra guard unit to be called.
  3. Enter the Telephone Group value.
    Defines the telephone group that represents the sensors in this group. These 2 digits make up the telephone number along with the last 2 sensors digits.

    Insert “01” on “Group of Telephones”. When Guard Unit will receive the call from the sensor, in the display will appear:

    This “0101” is the telephone address programmed on the audio decoder.
    Guard unit will be able to return the call just be pressing the guard unit “bell” key.
  4. Finally, Select the Time tab and indicate the time the sensor must be activated in order to generate the alarm.
  5. Save the data and create the Sensor Group.
  6. Repeat the process to create the second Sensor Group.
  1. Send all the configuration to the Central Unit 2405.


Do not hesitate to get in touch with FERMAX’s After Sales Department if you have any doubt or if you require any further assistance about this device.