Link Instruments MSO-19
The Link Instruments MSO-19 is a 2GSa/s oscilloscope, 200MSa/s logic analyzer, 100MSa/s pattern generator and a TDR. It is also extremely portable and is only $249 (including probe, clips, wires and software).
See Link Instruments MSO-19/Info for more details (such as lsusb -vvv output) about the device.
Hardware
Original software
Link Instruments ships the product with its FrontPanelTM Oscilloscope software. Software is for Windows only. Written in .NET (C#), without any kind of obfuscation, which makes it a real breeze to reverse engineer.
USB protocol
It's just serial-over-USB, supported by the Linux kernel through the cp210x driver, though as of Kernel 2.6.37 it needs to be patched to recognize the Link Instruments Vendor/Product ID (3195:f190).
iSerial was exploited by Link Instruments to store device probe methods, hardware type, hardware revision, calibration quirks and the actual serial number.
Serial protocol
Later.