Wireless GSM Desk Desktop Cell Phone Speaker SMS SIM Card Quadband 2G Network : GSM 850/900/1800/1900MHz External Interface  USB, for data configuration. TNC antenna interface: can be installed indoor antenna. Integrated Antenna (optional). Power Interface: single connector SIM card interface: standard 6 PIN SIM card interface Maximum transmitter power  850/900MHz: 33 +2 dBm 1800/1900MHz: 30 +2 dBm Receiver Sensitivity Better than-103dBm Power Specifications Switching Power Supply: AC: 100V ~ 240V DC: 5.00V, 0.8A Rechargeable Battery Type: Lithium Battery Capacity: 3.6V 720mAh (1000 mAh optional) Typical Talk Time: (according to your network environment) 2.5 hours (battery capacity of 720 mAh) 4 hours (battery capacity of 1000 mAh) Typical Standby Time: (according to your network environment) 72 hours (battery capacity 720 mAh) 90 hours (battery capacity of 1000 mAh) Dimensions (L  WX H) 221 mm  180 mm  72 mm Weight Less than 1000g LCD display: 128  64 dot matrix Providing the LCD backlight function Working temperature: -10  ~ +45  Storage temperature: -20  ~ +60  Relative humidity 5% to 95% 2. Product Features Support GSM standard; Support high-quality voice services (FR, EFR, HR speech coding); Support emergency call services; Support caller ID, call forwarding, call waiting, call hold, three-way calling and other supplementary services; Short message function; phonebook; Support DTMF secondary dial; (customer needs to customize) user personalization volume setting; Support polyphonic ringtones selection; Provide screen backlight; indoor antenna; Integrated antenna (optional); Provide battery, the battery is low and there is AC power, it can automatically charge the battery. Provide a variety of security solutions, such as lock network, lock card, modem card interlock (optional). This is a GSM wireless fixed telephone versatile, elegant appearance, providing basic voice, SMS, support phonebook and two storage modesSMS saved in SIM card or phone , it is the ideal choice for home communications products