Although sold under the Terra flag, the label on the back indicates that this modem was manufactured for Aztech under the UM9800 product name. The Terra V.90 USB modem is small for an external device - it's not a great deal larger than a packet of cigarettes. Notable by its absence is any form of power supply, because this USB gadget draws all the power it needs from the host PC's USB port.
Installation is laughably easy.
Plug the telephone cable into the wall socket. And, er, that's it. Since the modem takes over one of the available COM ports, it can be accessed by any normal Windows comms application, including dial-up networking, faxing and terminal emulation software. If you don't already have all that, the installation CD includes an application that can handle voice, fax and data for you, with the modem automatically switching between different types of incoming calls as necessary. Being a USB device, the Terra V.90 USB modem is hot-swappable.