US Robotics Courier 56K Business Modem. Modem speed: 56 Kbit/s, Interface: Serial, Type: External. Maximum fax transfer rate: 14.4 Kbps. Data link protocols: V.92, V.90, V.34, V.32bis, V.32, V.22bis, V.22, V.23, V.21. Certification: RoHS FCC approved (Part 15/Part 68) IC approved (ICES-003/CS-03) UL/CUL listed CE