1,fast sending sms 2,RS232 & USB & RJ45 3,800/850/900/1800Mhz 4,software support 5,serial port gsm modem The device built- ... IntroductionGSM MODEM pool also known as "SMS cat pool" in China, USB 2.0 can be used directly into the computer usb port, for laptops ... gsm modem Brief Introduction GSM MODEM pool also known as "SMS cat pool" in China, USB 2.0 can be used directly into the computer usb port, for ...