If power is cut off then restored in just a split second to a piece of electronic equipment that is turned on (or off)it will usually reset to standby (off) mode when the power is restored.

If you buy an IR543/Smarthome 4040 IR-to-X10 converter for $20 to $30 along with an X10 Appliance module for $12 you have all you need.

Discrete "OFF" would be:

Send IR signal to converter to send a "module off" command followed a tenth of a second later by an IR signal to the converter to send a "module on" command. If your component was on it will now be off and if it was off it will stay off.

Discrete "ON" would be:

Same as above to put the component in an "off" condition then send an IR "power" signal to turn the component on.

Unfortunately this won't work in my specific case because my Digital cable box has to go through an elaborate "boot up" that can take several minutes even with the shortest power interruption. I think it would work for almost all other equipment out there for only about $35.

Am I right about this or way off base?

Bob V.

How about
ON = X10 - on + DCB - Power
OFF = X10 - off
Is there a reason it will need to be Powered when off?

You're probably right in most cases except where the device has things programmed into it that might get lost if the power is off for an extended period of time.

Both my Denon AVR-5700 and Sony TA-9000ES turn themselves ON in case of power interruption.

In that case you could use commands as follows:

Discrete ON:

1.) IR command to X10 converter to send "module OFF" command.
2.) .1 sec. delay
3.) IR command to X10 converter to send "module ON" command.

Discrete OFF:

1.) IR command to X10 converter to send "module OFF" command.
2.) .1 sec. delay.
3.) IR command to X10 converter to send "module ON" command.
4.) .5 (+ or _) sec. delay.
5.) IR "Power" command for device.

How safe will it be for the device being controlled if the AC power is spiked off and on frequently?

The only downside of this idea is the surge as you turn the equipment on and then off for that split second on the power supply and any electrical noise that it causes entering the equipment

Good points. I wonder if there are any electronic engineer types here that can answer the question:

Would it hurt AV devices to have their power turned off and back on quickly on a regular basis?

Many devices these days are rated on "power cycles"... so unnecessary switching will generally wear things out somewhat quicker.