Pioneer VSX84TXSi receiver being controlled by RS232 from RP6/T3. Original installation was about 5 months ago. At that time the setup, SA8300HD cable box and Samsung Blu-Ray DVD (both HDMI through AVR to PRO-FHD1), worked flawlessly.

Per client email, system won't play DVDs, and after a site visit, I discovered that the AVR is not responding to the RS232 input commands. It turns on and off, and steps and ramps volume, but no input change. It sees the command, because it flashes "Cannot Select", just no operation.

It does switch with the original IR remote, and changes input manually (front panel) as well. I've removed/reset power to the AVR, and tried switching with a DVD loaded and without. Checked all connections, although all audio and video and control signals are working as expected, except this.

I can't see how a corruption could have occurred to just those to input commands ("19FN\r" and "20FN\r"), but I will reload the RP6 later today.

Any ideas?