# Soundtraxx + Airwire board hookup



## pimanjc (Jan 2, 2008)

Is anything special required to hook up a Sierra Sountraxx board and triggers to an older Airwire board? I'm sure this has been answered previously, but I didn't find it.

Thanks,
JimC.


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## Stan Cedarleaf (Jan 2, 2008)

Jim... You certainly can trigger the Sierra board with the Airwire Decoder if you use a TCS-TF4 interface. 

Here's a couple of images from an Airwire installer. The TCS-TF4 is on top of the receiver itself. That works right nicely...



























And the explanation. 

This is a pre G2 board builtup with a sierra sound board. Sounds are triggered from a TCS-TF4. The Sierra is configured per bulitin #6 from sierra. The small gold resister in the lower part of the photo allows for the use of up to 15volts of battery input. The resistor is a 5ohm 10 watt, metal case. Cables attached are set up for a 12VDC gel cell or a pair of Nimh 7.2VDC batteries.


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## East Broad Top (Dec 29, 2007)

Stan, why the need for the resistor? I've always just plugged my batteries directly in to the Sierra board without any troubles. (14.4 NiCad/NiMH, and now 14.8 Li-Ion) They both exceed 15 volts at full charge. I've been doing that for, well, how long has Sierra been around? I don't think I've ever not done it. 

Later, 

K


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## Stan Cedarleaf (Jan 2, 2008)

Kevin... I've known the gentleman who does those installs for 10 years and he's always used the resistor. It's just the way he does it and it's been very successful for him.









I personally don't use them on my installs, I was just trying to show Jim that the TF-4 is what he can use to trigger the Sierra board with Airwire. I had those images in my files which described it better that I can with words.









Jim, you might check with Jonathan at Electric Model Works for the TF-4.


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## Paul Burch (Jan 2, 2008)

Stan,
The TCS decoder is a FL4,not TF4. The TF4 is the one put out by Sierra. Both will do the same thing. The one pictured looks like the FL4.


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## East Broad Top (Dec 29, 2007)

Stan, thanks. Didn't know if I was missing something or what... 

Later, 

K


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## Greg Elmassian (Jan 3, 2008)

Stan, maybe some time you can ask this gentlemen, we might all learn something important, or another safety factor to consider. 

It could have 2 functions, most likely there to limit the inrush current of the Sierra. I would think it's not too bad, since there's no cap or battery on the Sierra itself. 

It could also drop the voltage to the Sierra, but unless the Sierra is drawing a fair amount of current it won't do a lot; but at 1 amp it would lower the voltage 5 volts and dissipate 5 watts, it could make some heat. 

I don't know the current consumption vs. voltage on a Sierra. 

Interesting. 

Regards, Greg


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