GSM Coin Payphone with Working Frequency of 850/900/1,800/1,900MHz, Low Power Indication.. Country of Origin:China (mainland)Brand Name: ... signal strong/feeblenessWall-mount/desktop compatibleFixed/remotionAuto collect coinsLow power indicationPower supply: Inside payphone battery NiMH, 6V DC, ... L/C at Sight GSM Coin Payphone with Working Frequency of 850/900/1,800/1,900MHz, Low Power Indication