Thank you Tony,

Many times blocking diodes are not really necessary, but, since many will read these posts, and there is no way to know what different types of equipment someone will try to apply it to, I felt it responsible to stay on the safe side.

Bottom line is that, if you use the blocking diodes, your equipment is safe from any backfeeding, and will work.

Without the diodes, it might work, might work intermittently, might not work, or might damage something. You have to rememeber.... it is not Infrafed going through the wires, but DC voltage pulses representing the pattern of the IR.

No sense taking the chance. Diodes are too cheap and too easy to use.