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 weak coverage. Compatible with PABX, alarm systems, recording systems, and more. Plug Type: EU Plug, suitable for use in Indonesia, Germany, France, Italy, and other compatible 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 to prevent signal interference. Step 3: Connect your 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. There is one communication port on the side of the terminal, allowing connection to one desktop phone. Step 4: Connect the power adapter and turn on the power. Step 5: Wait briefly for the device to acquire a GSM signal and enter normal operation 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: The package includes only the items listed above. Other accessories or products are not included. Light reflection and differences in display screens may cause slight variations in color between the product image and the actual item. Measurement error allowance is +/- 13 cm.