Because DVB equipment is used to process the MPEG II at many levels (including Cable headends and satellite uplinks)and is much more available than ATSC only gear. When we built WKPC-DT in 1999, we were aware of the PID conficts and since DVB equipment was abundant and ATSC only gear is /was not.. it was a simple matter to steer clear of anything below Hex 30 to avoid the problem in the first place. Right now I have three SD encoders at a remote location and I can put any or all of those feed directly on our DTV system by simply PID steering them with our muxes. I also have cable companies who are doing the reverse and by staying away from the lower PIDs it makes it a lot easier and they don't have to go to baseband at any point. Never think of ATSC only when planning a plant.. We use ASI for the distribution and go to SMPTE-310M at the last unit before the DTV transmitter.. William KET ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.