yes, now i get it)
i guess http://www.usbee.com/dxtb.html this will be it

Digital Signal Generator

The USBee DX has the ability to generate (output) samples from 8 or 16 digital signals at up to 24Msps or 12Msps in Signal Generator mode.

In this mode, there is a single buffer that stores the samples to generate. Each sample is a long value made up of 4 bytes. The low order 2 bytes represent the 16 digital channels. Digital Signal 0 is bit 0 of each long value. The high two bytes are not used. These samples can then be generated on command.

The maximum sample rate that is possible Signal Generator mode is 24Msps. This value can depend on your PC system and available processing speed and how many byte lanes are generating data. The basic rule of thumb is that the maximum bandwidth through USB 2.0 is near 24Mbytes/second. Therefore to generate 2 bytelanes (16 digital channels for example) would equate to a maximum sample rate of 12Msps.

The method for generating a single output pattern using the Signal Generator routines is as follows:

Allocate the sample buffer (MakeBuffer())

Fill the sample buffer with the pattern data you want to generate.

Start the generation running (StartGenerate (…))

Monitor the generation in progress to determine if it is triggered, filling, or completed. (GenerateStatus()).

Terminate the generation. (StopGenerate())

The USBee DX can not generate analog output voltages using this mode. Variable analog outputs are possible using the PWM Controller and an external RC circuit.

i don't know is these C-commands or not thought