brand new and high quality. Use SIM300W module with strong signal and good stability; No need for ground wire line investment, easy installation; Comes with timing, billing, and checking functions (for public phones); It has the functions of receiving signal strength display, working status display, and caller ID display; The operation method is the same as that of ordinary telephone landline; Fully automatic IP function (can be preset through the phone); Can be connected to the voice box, anti-theft alarm host, and meal order software on the market; Feature: 1. Adopting 300W communication module, with the best signal, long-term working stability, clear sound, no noise, no dropping when calling, even in remote mountain areas, signal receiving is also very strong. 2. There are large LCD display in Chinese and English, display signal reception intensity, specific for time, call records, call for time, call cost. 3. With the real billing function, alarm function with multiple charging mode, can be used as a public telephone, completely eliminate billing, cost savings. 4. Support all SIM cards that ordinary mobile phones can use. 5. It has the functions of hands-free dialing function, re-dialing function, caller ID display function (can also see the incoming call number), incoming calls, Dialed calls, missed calls. 6. The rate can be set automatically by manual or factory. can research multiple groups of incoming call or dialed call for time, records, call cost 7. The 2 common telephone interfaces can simultaneously connect to 2 ordinary telephones, and the utility model is convenient for connecting two telephones. Specifications: Operation mode: GSM 900MHz/1800MHz dual frequency Max power: 2W Power consumption: static state 25 mA, launched 600 mA Sensitivity: -104 dB Internal voltage: for DC 5V / 1A Environment temperature: 0 ~+40 Operating humidity: 45% to 90% (without dew) Atmospheric pressure: 86~106 kPa Environment noise: