The RCT-Tx20
transmitter

Key features of the RCT-Tx22 transmitter

The RCT-Tx20 is a feature-packed hand-held transmitter which is designed specifically for use with model trains. In addition to the speed control knob, it has a direction switch (which is used either for changing the loco's direction or for controlling accessories (via Channel 3)), a bind button (which can also be used for controlling accessories via Channel 5) and two additional function buttons (for Channels 2 and 4).

If you are new to battery power, radio control or to RCT and/or Deltang, then you might want to take a look at the FAQs (Frequently Asked Questions) in the Support section. Below is a quick tour of the key features of the RCT-Tx20 to help you decide if it is the transmitter for you.

The RCT-Tx20 is housed in a convenient hand-held case. Because it uses 2.4gHz radio control technology, the short aerial (antenna) is housed inside the case, and yet the transmitter has a range of up to 30m (100 feet), which is more than sufficient for most garden railways.

The transmitter is powered by a 9v PP3 battery which is inserted in a battery compartment accessible in the base of the transmitter. I find that one alkaline battery usually lasts about a year - but that of course will depend on how frequently you run your railway.

Speed knob
The speed knob controls Channels 1 and 6. It is a 300° rotary control with 'centre click'. The knob can control speed and direction or just speed when used in conjunction with the direction switch. This depends on how the receiver has been programmed (see Receivers

Direction switch
The direction switch controls Channel 3. With receivers programmed for 'centre off' control (ie when the speed knob is used to control both speed and direction), this two-way switch can be used to switch on lights or trigger sound effects on a soundcard. When used with 'low off' receivers, it is used to control the direction of the locomotive while the speed knob only controls the loco's speed - stopped when turned fully to the left, full power when turned fully to the right . See the Receivers section for more information.
 
On/off button
The illuminated push-button turns the transmitter on and off. The LED also provides information for the user - it flickers when inertia control is active (ie when the loco is speeding up or slowing down under inertia control) and it flashes once a second during the binding process (see Bind button below)

Bind button
Momentary push-button. Receivers need to be 'paired' with the RCT-Tx20. The binding process is only necessary once per receiver. To bind a receiver to the RCT-Tx20
    1. Turn off the RCT-Tx20
    2. Put the receiver into bind mode (eg with the RCT-Rx65b, switch it on and wait 20 seconds until its LED flashes rapidly). 
    3. Press and hold the bind button on the RCT-Tx20
    4. Switch on the RCT-Tx20 and then release the bind button. 
    5. Binding is complete when the LEDs on the transmitter and the receiver stop flashing. 
 Once the Tx is switched on, the bind button can be used to control receiver outputs via Channel 5 (eg to sound the whistle on a soundcard)

Function 1 (F1)
Momentary push-button. Pressing the F1 button sends Channel 2 on the receiver 'low'. Depending on how the receiver has been programmed, this signal can be used to trigger sound effects on a soundcard (eg turning on or off a soundcard, triggering a sound effect such as the sound of the safety valve or loco horn), or it can be used to control lighting (eg turning on and off a headlight, turning on and off interior lighting).

Function 2 (F2)
Momentary push-button. Pressing the F2 button sends Channel 4 on the receiver 'low'. Depending on how the receiver has been programmed, this signal can be used to trigger sound effects on a soundcard (eg turning on or off a soundcard, triggering a sound effect such as the sound of the safety valve or loco horn), or it can be used to control lighting (eg turning on and off a headlight, turning on and off interior lighting).


For the more technically-minded
The transmitter is capable of using seven channels. Channel 1 is used for speed control, Channel 3 is used by the direction switch, Channel 5 is used by the bind button and so can be used to control accessories when not being used for binding (eg I use it mostly to sound the horn or whistle on locos with soundcards), Channels 2 and 4 are used for controlling accessories - their output from the receiver is dependent on how the receiver has been programmed (see below). I have used the function switches (F1 and F2) and the Direction switch outputs (F3 and F4) to trigger the four additional sound effects on the MyLocoSound Universal soundcard (ie, guard's whistle, safety valve, pump and bell (to sound the departure of a train as per the Southwold railway))

Bind Button functions summarised
The Bind button can be used as follows: 
  • If the Bind button is being held down while the Tx is switched on, the Tx will enter Bind mode (see above). 
  • If the Bind button is pressed for less than 20 seconds at any time, it will normally control Channel 5. 
  • If the Bind button is pressed for 20 seconds or more within the first 60 seconds of switching the Tx on, it will perform calibration.

Reprogramming the RCT-Rx65b receiver with the RCT-Tx20
It is possible to use the RCT-Tx20 to change settings in any RCT receiver such as the RCT-Rx65b. However, there is a risk that you may accidentally reprogram a receiver to act in unexpected ways and so only reprogram a receiver if you are confident with what you are doing (for more information on programming see the Support section). If a receiver is put into programming mode by mistake, switch the receiver off back on again. 
 
To put the RCT-Tx20 into programming mode:  
  1. Make sure the Direction switch (Ch3) is in its central position. 
  2. Put the Throttle cojtrol knob into the 'off' position.
  3. Hold down both the F1 and F2 function buttons
  4. Switch on the RCT-Tx20
To make changes to receiver settings: 
  1. Switch on a receiver which has previously been bound to the RCT-Tx20.
  2. The receiver LED should start flashing rapidly within a few seconds to show it is in programming mode
  3. Release the Function buttons on the RCT-Tx20
  4. The LED on the receiver should now start flashing once a second with a one second pause.
  5. Push the Direction switch (Ch3) to the left and centre again to Adance the settings within a particular level. 
  6. Push the Direction switch (Ch3) to the right and centre again to Accept a setting for that level. 
For more information on programming receivers see the Support section and/or my blog posting on programming receivers
 
To disable the programming mode: 
  • Switch the transmitter off.