You can make local, domestic, and international calls using this terminal when connected to a desktop phone and a SIM card. Suitable for alarm systems. Compatible with GSM 850/900/1800/1900 MHz networks, widely supported by various carriers. Simple to install and easy to maintain. A directional high-gain antenna can be connected to improve signal reception in areas with poor coverage. Compatible with PABX, alarm systems, recording systems, and more. Plug Type: EU Plug, suitable for use in Indonesia, Germany, France, Italy, and other regions. How to use this device: Step 1: Install a SIM Card Insert the SIM card only when the terminal is powered off and the AC adapter is disconnected. Step 2: Connect the Antenna Use a mobile phone to locate the area with the strongest signal, then position the antenna accordingly. Avoid placing the antenna too close to the terminal, as it may interfere with signal performance. Step 3: Connect the terminal to a desktop phone To make calls, connect the telephone line to the RJ11 phone port on the GSM terminal and the telephone set. The terminal has one communication port on the side, allowing connection to one desktop phone. Step 4: Connect the power adapter and turn on the power. Step 5: Wait a moment for the device to acquire a GSM signal and enter normal operating mode. Step 6: Make calls using the connected telephone set. Specifications: - Network support: GSM 850/900/1800/1900 MHz - Frequency range: GSM 850 MHz (Transmit: 824849 MHz, Receive: 869894 MHz) GSM 900 MHz (Transmit: 890915 MHz, Receive: 935960 MHz) GSM 1800 MHz (Transmit: 17101785 MHz, Receive: 18051880 MHz) - Operating voltage: DC 5V12V - Telephone line length: 150 cm - Color: White - Material: Plastic - Dimensions: 120 x 85 x 28 mm - Input voltage: AC 220V Package Contents: 1 x Wireless terminal 1 x Antenna 1 x EU plug 1 x Telephone line Note: Light reflection and differences in display settings may cause slight variations in the color of the item shown in the image compared to the actual product. Measurement error allowed is +/- 13 cm.