QSI AirWire & GWire cab


This page details the receivers used in conjunction with the QSI Revolution or Titan to give compatibility with AirWire systems.

It also details the Gwire cab that can be used on an AirWire system

So, the QSI decoders can either handle varying DC voltage (normal track operation), or "remote control mode", where constant power is applied from the “track” leads on the decoder.

In this mode the QSI decoder responds to DCC.

If you put the decoder in "AirWire/Gwire" mode then it can be controlled from an Airwire and the NCE Gwire throttles.


This requires an optional receiver, detailed below.

There are some programming changes that are useful using AirWire, mainly concerning what the QSI should do if it does not "hear" signals for a while. Specifically, CV11 sets the "shut down delay time", how long the receiver will run without hearing a signal. Many people set this to zero, so the loco stays at the same speed, even if something is blocking the radio signal temporarily. If you do this, CV29 bit 2 must be off (no analog/DC mode). Remember if you do this, your loco will keep going no matter what until you slow it down. If your transmitter batteries die, your loco keeps going.

Overall, many people are very happy with this setup, and it works well. In my opinion, most "glitches" have more to do with the difficulty of programming CV's through the AirWire, not the QSI. The AirWire programming interface is cumbersome in my opinion. The QSI can verbally confirm CV programming though, a godsend in this situation.

The receiver hardware

AirWire runs on 900 MHz, the ISM band. Back in the day, this was a crowded band with all kinds of wireless stuff using it, as well as cordless phones. Since everything has gone to 2.4 GHz, it's now remarkably "quiet" and useful.

There is nothing magic about AirWire, it basically puts DCC over the air, with no changes to enhance it's error correction, resistance to interference. The AirWire and QSI receivers are basically just converting the DCC signal to the same thing over the air, basically just a modem.

There is a flex cable that plugs into the decoder, and a small receiver board.

The cable and socket have 5 connections, but only 4 are used, and 2 of them are ground, one is power (+5v), and one is transmit. The system never reads anything back from the loco.

Pin 1 gnd
Pin 2 NC
Pin 3 +5v
Pin 4 xmit
Pin 5 gnd

Receiver hardware versions

Below is the original version from QSI, with the original Linx module.


and the back side:

Pins on the connector are: Pin 5 is on top left (the connector is bottom right

5  top left - ground
4  connected to RX - (silkscreen wrong! there are 2 RX+ on the silk screen)
3  +5 volts (notice thicker trace)
2  RX+ (not really used)
1  bottom left - ground



Note the rotary switch that sets the channel (the QSI receivers only work on the original 8 AirWire channels).

below is a picture (courtesy of Ray Shoop) of the GWire receiver "topless", just for fun.

New receiver chip:

The manufacturer obsoleted the original chip, then took over a year making the new one, and the first batches were bad and they needed to redesign the chip again.

Clearly it is smaller, a surface mount vs through hole. (this delay in production helped fuel the demise of QSI solutions)




 A new receiver from an independent vendor

Recently an independent vendor has offered a receiver that will work with the QSI/Airwire/Gwire setup.

Here's the link:



he's done a great job and has it very reasonably priced.


The flex cable


I cannot emphasize this enough, even people I warn about this get it backwards. The cable only has connections on one side. Likewise the sockets on the decoder and the receiver.

Be careful, you can rip the thin connections from the cable easily!

The most important thing to remember is that when the receiver is enabled, the QSI takes it’s control commands from the radio receiver.

 (Most people add a SPST switch to disable the Gwire to allow it to take it's commands or programming from the track inputs)



Flex cable in receivers:

100 1020

The connectors go face up, away from the receiver circuit board (both types). The instruction sheet actually shows this in the picture and it explains this in the text.

Flex cable in the revolution:

For the Quantum Revolution board, the contacts face away from the center of the board, i.e. towards the edge.


Flex cable in the Titan

For the Titan board, it's the other way, the contacts face towards the center of the board


Replacement flex cables

Al Fischer found the exact cables in different lengths for a great price: (very expensive from CVP)

These are by Parlex, 1.0 mm pitch, 5 conductor, you can buy them from 2 to 18" long from Digikey. Here are some of the P/Ns.

HF05U-03-ND    (3")
HF05U-04-ND    (4")
HF05U-05-ND    (5")
HF05U-06-ND    (6")

Style 20566 – ul style 0.8 to 1.27 mm spacing

2308-564051  - 12 “ /  1mm spacing “same side”

Installing a QSI to use the AirWire/GWire receiver:

You need the QSI decoder in "AirWire" mode. Doing this is different for the QSI Revolution vs. the Titan.


Configuring the Revolution:

The Revolution senses that the receiver is plugged in, and will take it's commands from the receiver

Configuring the Titan:

First I do a track power install, with short address 3 to be sure installation is finalized, i.e. chuff is working right, start speed, etc.

I set the loco address now too.

Next, as a failsafe, I add the reed switch, to allow that reset, as if you put the titan into Airwire mode, it won't accept CV programming from the track inputs anymore. Be sure to test it!

Then set the airwire mode: CV 56.1 = 1 (if you don't have a second chuff switch, and you have not reversed the motor polarity)

at this point, add the receiver and try to control with the throttle


Note: it has been reported that old firmware on some decoders might not recognize the wireless mode. Update your firmware. This was reported on the FX-DO decoder (the O scale decoder)

AirWire cab/transmitter notes

Either the 1300 or 9000 will work, but because of some of the limitations in the 1300, I strongly recommend the 9000. In particular, F9 is used by the QSI, and the RF1300 only supports F0-F8. You thus lose some of the capabilities of the QSI. The QSI has a lot of capability, so I do not recommend saving $50 and limiting yourself.

If you do get the RF1300 throttle, most people remap the F9 key to one of the the available functions. (F9 is the disconnect and shutdown key).

Reprogramming AW 1300 transmitter:

Ray Shoop recommended remapping the functions on the 1300, and here's his tip on remapping the QSI F9 to the AirWire F7 button (thus giving up the QSI F7 Function).



/////F7 in NEUTRAL controls Shut Down\\\\
Enter OPS mode (Both direction leds start flashing) then
*49* Select CV 49
#9# Set Primary Index value
*50* Select CV 50
#1# Set Secondary Index value

"CV49 9"
*53* Select CV 53
#145# Set Feature ID = Disconnect/Standby/Shutdown

"CV50 1"
Exit OPS mode (Both direction leds stop flashing)
"CV53.9.1 145"

Reset the decoder:

full reset: 56.128.255 = 113  

cv 49 =128
cv 50 = 255
cv 56 = 113
(you should hear the system say "reset", if not you have done something wrong, the speaker is not functioning, or it is really dead, very rare, try it again)

Sometimes the sound just does not come back on, or the decoder appears erratic.  Note a full reset will set your DCC address back to 3 and reset all parameters to default. There's other forms of reset, that only reset certain things, see the manual.

GWire cab/transmitter notes

 NCE made the "GWire" throttle which has all the nice user interface design and operation of it's "Pro" series of DCC handhelds. Highly recommended.


General programming and operation tips:

Use the "announce feature" or CV64 to verify service mode programming, since there is no other way to confirm a CV has been programmed.

Don't leave the announce feature on all the time though, since some throttles can send commands too quickly and if the QSI is announcing a command, it may ignore a programming command given while it is "talking".


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