GSM Communicator GCM1000

Alarm systems
Monitoring of home appliances
Phone dialer, which works with all conventional models of alarm systems

For communication the device uses the GSM network for calling and the Short Message Service (SMS) (in future models of the device).

The device is working with GSM phones made by Siemens Company, but newer than C25 and A35 models.

The system has two inputs: IN1 and IN2. The outputs are also two: OUT1 and OUT2, which are contact systems of relays.
The contacts' parameters are shown in the following table. There are one normally opened and one normally closed contact on the each output. They are Galvanic disconnected from the rest part of the circuit..



Contacts current depends on the voltage

AC125V 15A

AC250V 10A
DC24V 15A

Max current allowed


Max continuous current


GCM1000 is a universal, highly effective and intelligent microprocessor system. One can use it to monitor climate system, electric devices, alarms, manufacturing processes, etc.

Principle of operation.

Principle of operation.

Connect a Siemens GSM phone to the phone connector. It is necessary that the GSM phone must be a model later than C25, but not A35. In programming mode it is necessary to program the phone numbers, which will be used to control the system..

After programming, the system is ready for work. The phone is connected to the PCB by a cable. Turn the power on. The red LED D8 lights up, and this is an indication that the system is in the active state, i.e. the inputs are active. The green LED D5 starts blinking with a frequency of 1 Hz. This means a correct circuit initialization and that the system is ready for work. The outputs are in a non-active state, and the respective indication is off (D6 and D7). The relay contacts are in the marked state. When any of both inputs became in short circuit state, the system is brought to its active state /this is only possible when D8 lights up/. In this state the relays are switched and the D6 and D7 light up. The cell phone will dial the second of the pre-set phone numbers. After about 20 sec. the OUT2 output will be deactivated.
The dialing to the number is about 2.5 minutes. After this time the dialing is stopped and the system starts dialing to the other pre-set phone number. Only two phone numbers might be set (programmed) in the system. This, described state (sequence) continues for about 10 minutes. For all that time the system makes 3 dials to one, and 3 more dials to the second pre-set phone numbers. After that, the OUT1 output and D6 LED are deactivated, the dialing is ceased, and the system leaves this alarm state. If any of both inputs is activated, the whole process is repeated.
In any moment a call from one of the two pre-set phone numbers might cease the alarm state. If this call continues until getting of two "No answer" signals, the IN2 input is deactivated.
The alarm is turned off by a call from one of the two pre-set phone numbers. The D7 LED blinks two times with a frequency of 0.5 Hz approximately. Then D8 LED turns off and the inputs are active no more. One can activate the system again by calling from one of the two pre-set phone numbers. OUT2 output and D7 are activated for approximately 0.5 second, after which D8 LED lights up and the system is enters the active state. IN1 and IN2 inputs are now active. If during the activation process the calling continues until getting two "No answer" signals, the system is activated, but the IN2 input is still inactive.

Operation modes

1. Push the pre-programming mode button (on the cable connecting the system to the cell phone)
2. Turn on the power supply for the system
3. D5, D8 and D9 LEDs light up
4. This state is kept until releasing the pre-programming mode button
5. On releasing the pre-programming mode button all LEDs light off
6. D8 LED blinks and stays on. This an indication that the "Programming" mode is active
7. Program the pre-set phone numbers by pushing the cell phone's buttons. Don't forget top turn on tone dialing when setting these phone numbers. The cable state must be as shown on fig. 4.

8. When pushing any of GSM buttons, D5 LED lights up, which means "don't push any other button for a while"
9. After entering 18 digits, which represent two the 9-digit phone numbers, the system leaves the "Programming" mode
10. D5 and D8 LEDs light up. The system waits for the button pushing
11. After the button pushing the system enters the normal operation mode

Normal operating mode:
1. The button is not pushed
2. Turn the power on
3. D8 lights up, D5 starts blinking
4. The system is ready for operation

Alarm activation mode:
1. The system is activated by any of the inputs only in active mode of operation, which is indicated by D8 LED
2. By activating any of the two inputs, the system is turned on, and both outputs are activated
3. The system dials any of the two pre-set phone numbers
4. After approximately 20 sec. the OUT2 output is deactivated
5. After approximately 2.5 minutes the calling is ceased and the system starts dialing the second number
6. This state of calling continues for approximately 10 minutes, in which the system makes 3 calls to one and 3 calls to the second phone number
7. After that the outputs are turned off
8. During all that time the activated alarm might be deactivated by calling from one of the two pre-set numbers
9. If that calling is longer until getting of two "No answer" signals, the active state is ceased and the IN2 input is made inactive

Activation and deactivation of the system
1. If the system is in inactive state, which is indicated by D8 LED that is off, the inputs don't influence to its work
2. The activation is made by one-time call from one of the two pre-set phone numbers
3. If this call continues until getting of two "No answer" signals, the system is activated, but IN2 input is made inactive
4. The deactivation of the system is also made by calling from one of the pre-set numbers
5. On activation OUT2 output is activated in about 0.5 sec
6. On deactivation OUT2 output is activated two times with a frequency of about 0.5 Hz

- Activation and deactivation phone numbers, and also the two phone numbers, which the system will dial when activating the alarm are one and the same two by two (all four numbers also might be one and the same)
- IN2 input might be used to implement a car alarm system. You can connect the SHOCK sensor to it. OUT2 output might be connected to the flashlights and the siren
- The system is absolutely protected against illegal entering and impact
- The system uses only 9-digit numbers. There is no need to write leading 0 when entering these numbers in "Programming" mode.


GM1000 - Price .



Orders: e-mail

From 15 May 2005 y.