-LeeThe BL34018 is a 28-pin surface mount SOP-28 RoHS telecommunications interface designed and manufactured by Belling-Lee. The interface has a controlled impedance of 100-200 (O) and is compliant with European Standard EN60950. Its operating temperature ranges from -40°C to 85°C, and an operating voltage range between 3V and 5.5V. The chip features an automatic switch/select mechanism, an operating selector switch, and low-cost construction. The device is suitable for use in a variety of applications including GSM, GPRS, EDGE, CDMA, 3G and 4G mobile networks.