中国300电话卡业务是一种凭电话卡自动记帐的国际直拨电话业务。使用国际300业务,用户可在任何一部双音频话机上,拨接入码“30090x”后,按照语音提示,依次输入卡号、密码,即可直拨国际电话。话费将自动记入持卡用户的 China 300 Phone Card Business is an international direct dial telephone service that automatically bills by calling card. With the international 300 service, users can dial the code “30090x ” on any dual-tone phone and follow the voice prompts to enter the card number and password in order to directly dial the international number. Calls will be automatically credited to the cardholder