I haven't used the High Out yet. But there's a job coming up where I might need it, so I'm gonna ask about it now:

1) Could it be used for a single flasher without a connecting block, at say 100 feet? How about at 40-50 feet?

2) Which breakout boxes have you used with the high out? We usually use the Niles MSU140 (which is powered, but I think it can run without the 12v wall wart as a passive unit). We've also used Xantech from time to time.

1) You'll burn out most flasher LED's if you hook up directly without using a series resistor to limit the current.

2) I've used a Russound connecting block without a wall wart, as the RP-6 has plenty of juice to power the block directly.

Put 100 ohms to 470 ohms in series with the LED when you feed it from the high out. Xantech's standard output uses the 470 ohm value, and those products that allow you to switch to a higher LED output use 100 ohms.

You can use three or more emitters in parallel without the resistor. If you use the connecting block just run high out and ground to the blocks input, use a separate power supply for the connecting block

Are there any disadvantages to using the High Out for a connecting block in close proximity (3 ft) to the RP-6 rather than one of the 6 mini plug ports on the RP-6?? (so as to gain an extra RS-232 port on the RP-6)

You loose the advantage of having an assignable output. That’s about it.

I haven't looked at the spec for the RP-6 lately, but I checked the RP-1 yesterday and it said it could put out 200 mA on the high output. That is enough to fry six or seven LEDs in parallel. I would avoid that.

If you use a connecting block, you are putting a resistor in series with each LED, lowering the LED current to a level safe for the LED. And some devices won't respond to an extremely hot IR signal anyway.

Another issue about LEDs in parallel is that they have to turn on at exactly the same voltage to be used without individual resistors, pretty much meaning they have to come from the same manufacturing batch.

Any wire that you run to some LEDs in parallel will have some resistance; let's say you have three LEDs, and they turn on at 2.55, 2.56, and 2.57 volts. For the purpose of thinking this through, let's imagine the LED voltage ramps up from zero to three volts. As long as the voltage is below 2.55, there will be no current flow. As soon as the voltage scooches above 2.55, the LED will allow current to flow and the wire resistance will limit how much can flow. As the voltage increases more, more current flows through the LED that has turned on at 2.55 volts, and the voltage does not increase! Why? Because as more current flows, the wire resistance increases its voltage drop.

That's the theory; in practice you might get some output from the LED that turns on at 2.56 volts, and perhaps even from the one that turns on at 2.57 volts when you are driving the crap out of the first one. But this is a bad idea -- "MIGHT" is not what a control system is about.

From what I've read, multiple emitters should always be wired in series, not parallel. I do this all the time to make double emitters from 2 singles. (when I don't have double emitters handy, or when I've already committed to using singles, and then discover I need one more.)

The only thing bad with emitters in series is when goes bad..both dont work..Although I have only had that issue one time in 15 years..or if you have a bad out of the box emitter, troubleshooting can be not so fun. Again have only had a few bad ones DOA

We usually use a Xantech CB60 with the RP-1, just use a Mono mini plugged into the CB60 with a long wire connected to the RP-1, no power needed and gives you 6 IR ports, all ports have a 100 ohm resistor in series on each port

I usually Hook it up like an Emitter expander Shown on page 2 of the istallation manual
[Link: xantech.com]

fluid-druid's approach is a good one. I prefer blink-LEDs, meaning that they are both IR and visible, so I can see what is happening; this takes care of knowing whether one has blown.

Glackowitz's approach with the CB-60 is perfect. The 789-44 has the same electronics, meaning one series resistor per LED, with the disadvantage of only four outputs and the advantage of a terminal strip. The CB-60, if I remember correctly, requires miniplugs for all connections, so putting it at a distance requires a splice to a short cable with a plug, or soldering a mini stereo plug. I'd rather just screw down wires.