If I only have a 4 emitter ir block how many emitters can I put on one port? I know that I can get dual emitters but what if I need more than 8 to control all of my a/v stuff plus lighting?

If you need more than eight emitters, then you need a bigger block... Sooner or later it won't have enough juice to run them, and they will either all stop working, or be intermittent.

There is no substitute for the right tool.

Xantech has a 6-output block with only one drawback: all inputs and outputs are mini-plugs. It has no screw terminals. Amplified blocks are also available. I have used the ten-output block with zero problems.

Oh, yeah, and there is another way to create more outputs. Each output of a block is simply the input going through a 470 ohm or 100 ohm resistor to an LED. Each LED has its own resistor in series with it, like so:

Sensor Positive out -----------resistor-------------LED positive
Sensor Negative-------------------------------------LED negative

The 100 ohm resistor is rarely used as enough IR comes out of the LED when a 470 ohm resistor is used. Also, one LED with a 100 ohm resistor takes as much current as five LEDs set up with 470 ohm resistors, so I wonder why I even mentioned it...I know: so you will know that some circuits provide a lot of current, but the 470 ohm approach is the better one.

Anyway, when I used the amplified ten-output block, I ended up needing thirteen outputs, and I created three more by using three 470 ohm resistors and three more LEDs.

If you have any question about how to wire this, email me and I will create a better pseudo-drawing for you.

I'm reviewing the Xantech range for the first time, with a view to installing an IR distribution system, and I'm not aware that ANY of their single-zone connecting blocks for IR emitters have screw terminals.

As far as I can see, Xantech has standardised on the use of 3.5 mm mini jack plugs/sockets.

[Link: speakercraft.com]

"Each output of a block is simply the input going through a 470 ohm or 100 ohm resistor to an LED."

The input is demodulated serial IR data, feeding this to an LED would cause it to flash at the data rate, with no modulation, resulting in the signal being ignored by an IR receiver module.