English: Eye pattern of a 1000base-SX Ethernet data stream, converted from optical to electrical using a SFP module, digitized with a Teledyne LeCroy WaveRunner 8404M-MS oscilloscope, and rendered with glscopeclient. This is a NRZ signal, since the eye has only two levels (logic zero and one). Unlike this image deliberately uses only a few thousand UIs in order to illustrate the impact of inadequate measurements on eye quality.