There are several added functions and specs from TDS3000 to TDS3000B series as detailed below: Added WaveAlert............waveform anomaly detection Added E*Scope..............web based remote control Ethernet port is now standard Added an External Trigger Added XY Cursors Added Save All Waveforms function Added Delay and Phase measurements 10X better timebase accuracy............20ppm vs 200ppm Added Compatibility with P67XX O/E converters TDS3TRG and TDS3FFT is now standard in ALL TDS3000B series scopes Added optional Advanced Analysis module (TDS3AAM)..........Area Meas, Cycle Area Meas, Int, Diff, FFT, Arbitrary Math Expressions (example: CH1 - Mean(CH1)), Measurement Statistics (both min/max and mean/std deviation) Added optional Limit Test module (TDS3LIM) Added Optional Combined GPIB/RS232/VGA (TDS3GV) Added Plug-in Thermal Printer (TDS3PRT) Removed Tutorial Training. Customers can order the TNGTDS01 Here is the list of changes from the TDS3000B series to the TDS3000C series (all the functions or features that were added to the TDS3000B from the TDS3000 also applied to the TDS3000C model): Replaced the floppy drive to a USB host port for the USB flash drive support All models are shipped with one probe per channel.  Old TDS3000C's with P6139A and current TDS3000C;s with P6139B. Only the 100MHz, 300MHz and 500MHz model are available Removed the Centronics port Removed the 15V DC output