You can make local, domestic, and international calls with 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. Easy to install and maintain. A directional high-gain antenna can be connected to improve signal 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, Spain, 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 unplugged. Step 2: Connect the Antenna – Use a mobile phone to locate the area with the strongest signal, then position the antenna there. Avoid placing the antenna too close to the terminal to prevent signal interference. 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. 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. Step 6: Make calls using the connected telephone set. Specifications: 1. Network support: GSM850/900/1800/1900MHz 2. Frequency range: - GSM 850MHz (Transmits: 824-849MHz, Receives: 869-894MHz) - GSM 900MHz (Transmits: 890-915MHz, Receives: 935-960MHz) - GSM 1800MHz (Transmits: 1710-1785MHz, Receives: 1805-1880MHz) 3. Operating Voltage: DC 5V-12V 4. Telephone line length: 150cm Color: White Material: Plastic Dimensions: 120 x 85 x 28mm Input Voltage: AC220V Package Contents: 1 x Wireless terminal 1 x Antenna 1 x EU plug 1 x Telephone line