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. 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 countries such as Indonesia, Germany, France, Spain, and Italy. 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 there. Keep the antenna at a distance from the terminal to avoid 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 a moment 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: GSM 850/900/1800/1900 MHz 2. Frequency range: - GSM 850 MHz (Transmits: 824849 MHz, Receives: 869894 MHz) - GSM 900 MHz (Transmits: 890915 MHz, Receives: 935960 MHz) - GSM 1800 MHz (Transmits: 17101785 MHz, Receives: 18051880 MHz) 3. Operating voltage: DC 5V12V 4. 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