I have made a simple ht12d and ht12e circuit. They are communicating correctly but on the decoder pin 11 is only one volt. Pin 10, 12, and 13 are high will 5V and go to 0 when a tactile switch is pushed. I have switched to a new decoder but I still have the same problem. I've checked for any shortages but there is none. If anyone has a resolution for this problem please tell.
The schematic of your circuit is invisible so I cannot see what you have connected to pin 11. Maybe pin 11 has a high frequency signal that has narrow positive pulses so its average voltage is 1V.