USB 56K External Dial Up Fax Data Modem Dual RJ11 Ports Support Caller ID Computer Laptop Fax Modem for Windows for LINUX 1DUAL RJ11 PORT: The USB data modem utilizes dual RJ11 ports for connecting two fax phone lines or a telephone at the same time. 2SUPPORT CALLER ID: USB data modem adopts for Conexant93010 main chip, support Caller ID, compatible with AT and extended AT command set. 3EASY TO USE: USB 56K external modem is easy to use and supports stable fax sending and receiving. 4SUPPORT OS: Computer laptop fax modem supports for Windows 98/2000/xp/vista, for WIN7, for WIN8 , for WIN10, for WIN11,32/64bit, for LINUX operating system. 5ANTI THUNDER: Dual RJ11 Port USB fax modem is protected by fast anti thunder defend circuit to enhance thunder resistance.