Hi Kevin,
May I check with switcher are you using? Carbonite or Acuity?
Regardless of switcher, KEYPVW, KEYPV and KEYPST are invalid RossTalk commands. You can view supported RossTalk commands at the following link: https://help.rossvideo.com/carbonite-device-db/Topics/Protocol/External/CNT/RT-CNT-Comm.html
On a Carbonite switcher, if your objective is to view Key4 on the Preview of MEPP, you can do that by using the TRANSINCL command. This would set the Next Transition Area to include Key4, and puts it into Preview. The RossTalk command would be TRANSINCL ME:0:4
Hope this helps.
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Aaron
Business Development Manager - Production Switchers & Servers
Ross Video
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