DAVID GD-04 User Manual

GD-04 DAVID MKS51200_OS1 1

The GD-04 “David” GSM communicator

User manual

The GD-04 module got its name from David, a biblical king who outsmarted Goliath, a giant. In our
case, Goliath is meant to be the GSM network. We hope that the skills of your tiny David will help you
manage the giant.

1. Basic description

SIM

Bus connector

Battery connection

LED indicator

RESET jumper

GSM antenna

Tabs

SIM card

Output fuses

1.1. David provides:

• 2 output contacts of power relays X and Y (each allows up to 5A/250V)

• 4 input terminals A to D for SMS reporting (the inputs react to a connection or disconnection

to or from a common GND terminal)

GD-04 DAVID MKS51200_OS1

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1.2. David can be used as:

• A switch with SMS remote control. SMS texts for switching particular terminals on/off are

configurable.

• A time-switch which can be activated remotely via a mobile phone (the switch-on period is

configurable from 1 second to 10 hours).

• A relay with dialling-in remote control. Up to 50 tel. numbers can be authorized for each

relay. Because calls are not answered dialling-in control within GSM is free of charge. (David
only checks the caller’s number and – if the number is authorized – responds with relay
activation.) This can be used for parking latch control etc.

• A relay with validity-limited dialling-in remote control. Each authorized number can have

a limit to the number of calls. When the call count reaches the limit the tel. number is de­authorized. This can be useful for pre-paid services such as e.g. parking. Any tel. number can
be re-authorized via SMS by the administrator.

• An SMS reporter. Input A to D activations or deactivations can be reported by SMS and

optionally confirmed by phone calls. Each input can have its own message texts and up to 8
tel. numbers programmed.

1.3. David can be supplemented with:

• A GD-04A back-up module, which provides David with the ability to work approx. 12 to 24

hours continually without an external power supply, see 11.1.

• A GD-04D DTMF module, which allows you to control David’s output relays by entering

numeric codes (DTMF codes) on the telephone keypad during calls, see 11.2.

• A GD-04P link cable, which allows you to connect David to a PC through a USB port and

perform any desired configuration using GDLink software.

• A GD-04R radio module, which allows input A to D activations via wireless buttons or

detectors of the OASiS series and also provides David with the capability of output relay X or

Y state transmission to UC or AC OASiS receivers. In addition, you can control relays X or Y

“locally” via RC-8x keyfobs (so that an appliance can be controlled both via a mobile phone

and a keyfob). The module also allows heating control (again locally or remotely via a mobile
phone) using wireless thermostats of the TP-8x series.

A detailed description of optional accessories can be found in chapter 11.

2. David’s SIM card

• In order to function, David needs a SIM card, preferably a tariffed one.

• Test the SIM card by using it in your mobile phone – SMS sending and calling must work

correctly.

• Switch off the PIN code protection via the phone menu (or set the PIN code to 1234).

• Check the GSM signal strength in David’s location.

3. Installation

1. The GSM antenna should not be shielded by metals. If necessary, an external antenna

designed for the 900/1800MHz GSM band can be connected via a 50Ω SMA connector.

2. Open the cover and release the electronic circuit board by pressing the tabs.

3. Mount the rear plastic cover at the desired location.

4. Insert a SIM card: Open the SIM card case by shifting the moving part in the direction of the

terminals and tipping it off. Make sure that the card is correctly oriented and insert it. Close
the SIM card case (fold and re-shift the moving part).

5. Insert the circuit board back to its position.

6. Do the wiring, see below.

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4. Wiring

1. Power supply – use the +12V and GND terminals. Any power supply adapter used should

provide 12V DC voltage and up to 500mA of current. If an LT-89 mains adapter is used (a
recommended option) wire the grey marked conductor to GND. Do not turn the power supply
on until all input/output wiring has been done.

12V DC
power supply
( adapter)LT- 89

_

+

2. Output relay contacts – available at the X1+X2 and Y1+Y2 terminals. Each contact is fused

to 5A. The circuits which the contacts belong to are protected from the remaining electronics
by a safety separator and are capable of switching up to 5A at 250V AC. The following
example shows a light bulb control via the Y output relay:

230V/50Hz

Light bulb

3. Input terminals – marked A to D. The terminals respond to a connection or disconnection to

or from GND by sending an SMS report. No external voltage supply can be connected to
these terminals – they can only be controlled via a potential-free switch/contact. Example of
wiring a switch to input A:

Switch

5. Initial powering up

1. Turn the power supply on, registering to the GSM network is indicated by the LED flashing

(if no indication occurs, check the power supply wiring).

2. After GSM registration the LED stops flashing (usually within 1 minute). Continued flashing

indicates a GSM registration fault. Disconnect the power supply and check that a valid SIM card
has been correctly installed into the device, see 2 and 3).

3. Send the SMS instruction STATUS to David’s SIM card number.

4. David responds by a status report, e.g. STATUS: A0,B0,C0,D0,X0,Y0,GSM:80% (which

means that all A to D inputs and both the X and Y relays are switched off and that the GSM
signal strength is 80%). Depending on the GSM network traffic the response may take some

time. If no response occurs, verify that “STATUS” is spelt exactly right in the text of the

message and that you are sending the message to David’s correct SIM card number (repeat
the previous st ep) .