The Psitek GSM Interface can work in following configurations:

- as equipment of analogue line of PBX

- with analogue telephone

The pack contains:

- GSM Interface unit
- 12 Volt DC power supply
- GSM antenna
- Connector to telephone - cable
- Fastening to walls, two pegs ø 6mm
- User guide

Additional items that are required and not supplied:

- GSM SIM card
- Telephone cable to switchboard (PBX)
- RS232 cable - in case of connection of interface with computer PC

External describe



A) Preparing GSM gate to work

Your GSM Interface has been supplied with a telephone cable connector (3-pin plug), permitting on connecting with PBX (or with standard - telephone). The outer two connector are dedicated to “A” and “B” legs of the telephone wires and connector in the middle is used for connection to protective earth.

1. Using wire strippers, remove the insulation for about 5 mm from the two wires of the telephone cable,
2. Open the screw terminal (3-pin plug) connectors with a fine screwdriver,
3. Insert the two telephone wires into the outer two screw terminal connectors,
4. Tighten the screw terminal connectors. Ensure that all the wires have been securely fitted.


B) Preparing SIM card

Using a blunt object, such as fine screwdriver or paper clip, press the yellow ejector pin adjacent to the SIM card carrier. Remove the SIM card carrier and place the SIM card firmly into this carrier with metal contacts facing upwards. Carefully slide the carrier back into position until it is firmly in place in the GSM Interface.

Your GSM SIM card may carry a personalized PIN number for protection against misuse. For operation in the GSM Interface, this PIN number has to be programmed into the device. This can be performed as follows:

1. Prepare the unit for operation (see above),
2. Connect the power supply of the unit to mains power,
3. Connect a standard telephone to the device,
4. When the SIM LED starts flashing, press and hold the Maintenance Mode button until the LED lights up,
5. Lift the receiver of the telephone, and dial the following sequence on the keypad

*27*<PIN number of SIM card>#

After successful PIN entry, three short confirmation tones will be heard.

6. Turn off the phone. PIN is entered and Interface is ready to work. Right now PIN is programmed and stay there after it would be turned off. If SIM card would be changed, operation must be repeated.

Instead of PIN programming procedure there is possibility to turn PIN off from SIM card. If you want to do this contact your operator.

C) GSM interface setting

Device can be installed horizontally or vertically. Interface was projected with thought about use him inside of rooms. Device musn't put out on immediate activity of moisture and radiations solar.

  1. Connect telephone - cable to device.

  2. Connect GSM antenna to socket. For optimum - qualities of receiving, ascertain, that antenna is distant at least 1m from devices.

  3. Ascertain, that antenna cable is not taken in neighborhood of cables other telephone – devices.

  4. Antenna has to be found in vertically position, in distant place at least 30cm from walls, or other large objects, which would be able to make difficult access of radio - signal.

  5. For obtainments optimum - activities antenna should become placed on metal - support. This will assure suitable stability of antenna and will improve quality of signal.

  6. Connect power supply to interface.

Device is now ready to work. In some conditions device can even need to three minutes for log to GSM network.

Table below explains meaning of LED.

LED Indicator

Turned on

Turned off


Power supply (green)

Power OK

No power

To low power supply

SIM (yellow)



Quickly = SIM card damaged
Slowly = SIM card blocked
Pulsate = PIN code necessary

GSM Network (green)

Strong signal

Network searching

Slowly = low signal level
Quickly = strong signal level

Maintenance (red)

Programming mode


Quickly = error
Slowly = data transmission
Pulsate = when Power supply, SIM and GSM Network LEDs are on = call in progress

Table 1 Meaning of LED indicators

D) Disconnection of interface

Introduced below mean shows how correctly should log out device from GSM network and to separate power supply:

1. Press short maintenance button.
2. Wait till indicator GSM and SIM go out. Coefficient power supplies will flash in short distances.
3. Device is ready to separations of power supply.

Programming option of interface

Change of industrial arrangements which are in memory of the Psitek GSM interface can be executed perfect with three steps:

1. With analogue telephone with DTMF
2. From PC computer through data port using HyperTerminal and AT commands
3. From PC computer through data port using dedicated software

Technical specifications

Power requirements
Input Voltage range 100 - 240V AC.
Frequency 50 - 60 Hz.
Input Voltage 10.5 - 14.5V.
Input termination is by a 2 way pluggable screw terminal.

Power Consumption (at 12V DC)
90mA when the phone is on hook.
300mA at 2W during call mode.
Current burst 600mA at 2W.

Ringing Power Capabilities
Voltage – 55Vrms at Trapezoidal
Frequency – 25Hz (programmable 17, 25, 40, 50Hz)
Antenna Impedance – 50Ohm
Operating Temperature 0 - 50 C

Line Feed
Line length for max AB drive is 500 meters.
AB Loop current – 22.5mA or 30mA programmable
Line Reversal - Programmable soft line reversal
Meter Pulse frequency – 12 or 16KHz programmable
Meter Pulse amplitude – 500mVrms
Data Programming – AT commands at 9600bps.

The Dimensions of the unit 116mmx79mmx28mm (LxBxH)
The Weight is approximately 180g.
Material used – Aluminium extrusion
Mounting – Desk or wall mounting with bracket. Bracket supplied as standard.

Connection options
DC Input termination – 2 way pluggable screw terminal.
AB Line termination – 3 way pluggable screw terminal with centre earth.
Antenna Termination – SMA bulkhead jack.
Data/ Programming Port – RS232 through DB9 female connector.

GSM Interface
GSM Output 900 MHz – Class 4, 2W EGSM
GSM Output 1800 MHz – Class 1, 1W DCS
SIM interface – 3V mini SIM
GSM Data rate – Transparent and non-transparent to 14.4kbps.
FAX – Fax group 3 (class 1 and 2) through Data port.



Technical-Trade Office

Szczecin ul. Tuwima 21

tel. (+48) 91-8162249,

fax (+48) 91-4213131



Last edition:  2003-07-20