loss of packets; in case of TCP they are retransmitted (affecting the Round Trip Time, etc.) and, in case of UDP, transmission is discontinued-which is essential from the metrological point of view, as no altered waveforms could be transmitted. Moreover, in order to avoid such distortion, QoS configuration can forbid delivery of erroneous PDU-s. The subjective effect of good QoS was the "online" feeling due to real-time reception and remote operation by the graphic user interface ("skin") of the oscil- loscope emulated at the client side. For TCP DL transmission the radio interface allowed 40-50 kbps EDGE and the Time/Div. of the oscilloscope could be decreased to 1 us keeping the overall real-time transmission performance. However, starting with 5 ms (Time/Div.), some retransmissions were needed. For TCP UL the radio interface allowed lower rates and limitations of the real-time transmission effect was reached faster. For UDP DL, the real-time transmission effect was blocked faster than expected and the Time/Div. could only be lowered to 2 ms. For UDP UL the probe could transmit at lower rates and the "online feeling" was disturbed even more (the Time/Div. could be lowered only to 20 ms). This was caused by the fact that in GPRS/EDGE/UMTS there are less traffic channels or radio resources allocated for UL and their priority is lower compared to the down link channels. For noncritical data streaming applications, UDP packet loss could be ignored and transmission could simply continue (with newly received packets)-the effect could be an overall faster "noninterlocked" link (compared with TCP). The case study allocated the same attention to UL as for DL, because the tele- communication market-that was primarily targeting the download of content-is gradually shifting to upload access, allowing customers to provision content. More and more 3G operators will give importance to data streaming (mostly multimedia-as the forecast for the near future, but also industrial-as we illus- trated here) activating the QoS traffic