Features: A total of 200 houses and each family can preset two numbers for walkie talkie calls. When the visitor comes, just press the house number and #, and then start dialing the preset number. Dual relay output, dual alarm input port. When the visitor arrives, they press the call button and the device produces a high quality audio call with up to 2 digits announcing their presence. If the person answering the call wishes to allow access, they simply release the on-board relay by pressing the button on the handset. Allow 400 phone numbers to call the system for free to trigger the board relay to activate the door. This system provides two-way voice, caller ID, allowing known numbers to call the device. When the call arrives, it is immediately discarded, and if the number is known, the door is opened. Ideal for mobile phones, so up to 400 users can operate the gates this way. Even during a call, you can press the button on the phone's keypad to open the door for the visitor. A reusable battery can be connected internally for operation and alarms during a power outage, and the battery will automatically fail when the normal power supply is working again. It also alerts if the battery is low. Use a remote solar emergency telephone call point for GSM. Innovative waterproof lock design. Dial the number when the user presses the call button. You will be dialed up to 2 phone numbers, mobile or landline. Vandal-resistant design, rugged stainless steel call point with flexible polycarbonate solar panels that won't break. The front panel is installed without screws and is easy to install. Dual relay output for easy control of door openers or alarm components. Press the remote control relay output by pressing the button while talking to the visitor. The front panel uses the innovative KEY LOCK for a safer design. Unlimited range of wireless GSM intercom, button and visitor call. Authorized phone number to open the door, built-in GSM-KEY function, professional industrial grade GSM engine. Up to 40 phone number storage, allowing automatic access via calls and text messages. Specification: Condition: Brand New Color: Shown as Picture Material: Stainless Steel GSM Frequency: 850/900/1800/1900MHz Power Input: DC 12V Rechargeable Lion Battery: 3.7V, 1000mA (Excluded) Package List: 1 x GSM-house Box 1 x Antenna 2 x Key 1 x USB Data Cable 1 x USB Program Adapter 1、A total of 200 houses and each family can preset two numbers for walkie talkie calls. 2、When the visitor comes, just press the house number and #, and then start dialing the preset number. 3、When the visitor arrives, they press the call button and the device produces a high quality audio call with up to 2 digits announcing their presence. 4、If the person answering the call wishes to allow access, they simply release the on-board relay by pressing the button on the handset. 5、Allow 400 phone numbers to call the system for free to trigger the board relay to activate the door.