FrSky TANDEM X20 PRO Instruction Manual

Introduction

This manual provides detailed instructions for the FrSky TANDEM X20 PRO, a high-performance dual-band 900M/2.4G RF signal transmitter.

TD-ISRM PRO RF Performance

The TANDEM X20 PRO features a dual-band 900M/2.4G RF signal link with multiple operating combinations. It supports dual 2.4G TW RF mode and simultaneous activation of both TW and ACCESS R9 modes. This allows for the connection of TW and ACCESS R9 receivers via SBUS IN/OUT ports for redundant backup, enabling the simultaneous use of three different RF links for enhanced reliability in long-distance RC operations.

Comprehensive Functional Inputs & Solid-Quality Metal Parts

The X20 PRO integrates functional inputs from the TANDEM series, adding 2 extra trims for precise tuning. Levers on the sides of the transmitter's slider support customizable positioning. A self-locking button is located on the left and right sides of the handle top for flexible application settings. The main body is constructed with all CNC-machined metal material, and the central panel incorporates genuine carbon fiber. Primary input components like trim caps, slider levers, and knobs are made from metal, ensuring rugged quality and enhanced durability.

Built-in Mass Storage & Text to Speech Function

The X20 PRO includes a built-in 8GB flash storage for ample file storage and high data transmission speed. The Text-to-Speech (TTS) function allows for convenient conversion of typed English words into spoken speech, enabling the ETHOS system to flexibly match triggered operational status with generated speech files.

Overview

The transmitter features a display screen, power switch, multiple function switches (SA-SH, SK, SL), multi-position flap slider, angle adjustable extended slider, navigation controls (RTN, SYS, MDL, DISP, Page UP/Down, scroll, enter), speaker, hook, custom button, and 2.4G internal antenna. It also includes a USB port for upgrading and data management, and a Smart Port for firmware upgrades of S.Port devices.

Switch Functions:

• SA: 3 positions; Short Lever
• SB: 3 positions; Long Lever
• SC: 3 positions; Long Lever
• SD: 3 positions; Short Lever
• SE: 3 positions; Short Lever
• SF: 2 positions; Long Lever
• SG: 3 positions; Short Lever
• SH: 2 positions; Momentary, Long lever
• SK: Self-Lock Button
• SL: Self-Lock Button

Switches can be chosen and their positions defined in the HARDWARE menu.

Specifications

• Dimension: 200.5*213*84mm (L*W*H)
• Weight: 949g (Battery Excl.) / 1080g (Battery Incl.)
• Operating System: ETHOS
• Internal RF module: TD-ISRM PRO
• Number of Channels: Up to 24
• Built-in Flash Storage: 8GB
• Operating Voltage Range: 6.5 ~ 8.4V (2S Li-battery)
• Operating Temperature: -10°C~60°C (14°F~140°F)
• Operating Current: 600mA@7.4V (typ.)
• Charging Current: ≤1A ±200mA
• Recharge System: 2S Li-ion Battery (USB Type-C Interface)
• USB Adaptor Voltage: 5V+0.2V
• USB Adaptor Current: >2.0A
• Backlit Touchable LCD Resolution: 800*480
• Compatibility: ACCST D16 & ACCESS & TD & TW receivers
• External Module Bay: Lite Type

Features

• Built-in TD-ISRM Pro Dual-Band Internal RF Module
• 900M/2.4G Dual Band TD Mode
• Dual 2.4G TW Mode
• ACCESS 2.4G & ACCESS R9 Modes
• 2.4G ACCST D16 Mode
• Super Low-Latency and Long-Range Control with Telemetry (Up to 50 to 100KM range and down to 4ms end-to-end latency)
• 800×480 Resolution Outdoor High Brightness Touchscreen
• 6 Quick-Mode Custom Buttons (Front) and 2 Momentary Buttons (Rear)
• CNC Machined Metal Shell & Carbon Fiber Center Panel
• 2 Self-Locking Shoulder Buttons
• 2 Knobs & 6 Trims with All-CNC Metal Caps
• 2 Angle Adjustable All-CNC Metal Slider Levers
• All CNC High-Precision Hall-Sensor MC20 Gimbals with 10 Ball-Bearing
• Adjustable 45° / 60° stick travel
• 8° rotatable panel
• Built-in 8GB Flash Storage
• Text to Speech (TTS) Function
• Digital Audio Power Amplifier
• Built-in 6-axis Gyroscope Sensor
• High-Speed PARA Wireless Training System
• Built-in Audio Wireless Module (Compatible with Bluetooth Audio Device)
• Haptic Vibration Alerts and Voice Speech Outputs
• Dual-side Haptic Gimbal Feedback
• Upgraded Robust Antenna Handle & External LoRa Antenna Connectors

2S Li-battery Balance Charging via USB-C

The Green LED indicator states: Led on (charging), Led off (end of charge), Flash (charge fault). Battery compartment size: 84*41.5*20mm (L*W*H). Use a USB adapter (Voltage: 5V+0.2V, Current: >2.0A) for charging. Lower initial charging voltage improves charging effect when voltage difference between cells exceeds 50 mV.

Navigation Controls

The left navigation control handles RTN, SYS, MDL, DISP, and Page UP/Down. The right navigation control handles scroll and enter. Both navigation controls and the touch screen can be used to control the system.

Navigation Actions:

• Page Down: Short Click
• Page Up: Long Press

ETHOS Suite

The ETHOS Suite allows updating the radio bootloader, firmware, SD card, and flash, as well as converting image and audio formats. Download the latest information and the ETHOS Suite from ethos.frsky-rc.com. Ensure the radio bootloader is kept updated for optimal use of the ETHOS Suite application.

ETHOS Operating System - Create the Model

STEP 1: Enter Model Select, then select the model type (Airplane, Glider, Heli, Multi, Other).

STEP 2: Configure the model channel and name the model, then set the model picture.

Model Setup Procedure - Internal Module

STEP 1: Enable RF Module

Access the RF system menu via touch-screen or navigation encoder. Choose the Internal Module. Turn the state of Internal RF to On. Set the binding mode for the Internal RF module corresponding to the receiver (ACCST D16, ACCESS, TW, TD, and TD-Pro Mode).

Note: ACCESS 900M mode can be enabled simultaneously while using ACCESS 2.4G mode or Dual 2.4G TW mode with the internal module.

STEP 2: Channel Range Setting

The internal RF module supports 24 channels (CH1-8 / CH1-16 / CH1-24). Channel range is configurable by pressing the channel bars. Ensure correct channel configuration before using the module.

STEP 3: Model ID Setting

The system assigns a receiver number (Model ID) automatically when creating a new model. The Model ID can be set from 00 to 63, with the default ID being 1.

STEP 4: Registration

For TW Mode, select [Register] in the RF System-Internal Module tool to enter Registration status. Press the F/S button on the receiver and power the receiver on. When the "RX Connected" page appears, press [REGISTER] to complete registration, then power off the receiver. The system assigns a unique UID to the receiver.

STEP 5: Automatic Binding (Smart Match)

In the RF system menu, select the desired mode (e.g., 2.4G FSK). Move the cursor to RX1 [BIND], press it, and repower the receiver. Click the RX to complete binding after the receiver window pops up. The system will confirm "Bind succeed". Registration is not required to repeat if the receiver was previously registered.

STEP 6: RF Power Setting

The internal RF Module offers multiple RF power options for extended control range. Open the Power menu bar and select the desired power level.

Range Check

Perform a pre-flight range check to prevent signal loss due to environmental factors. Place the model at least 60 cm (2 feet) above the ground with the receiving antenna vertical. In the ETHOS system, navigate to "RF System", select "RANGE" mode, and press the Encoder. The effective distance is reduced to 1/30 in range check mode.

TTS (Text to Speech) Function

Step 1: Create a Special Function of "Play Text".

Step 2: Enable the function and set up an "Active Condition" for it.

Step 3: Configure basic settings by typing into an alphabet letter or English words.

How to set Failsafe

There are three failsafe modes: No Pulse, Hold, and Custom.

• No Pulses Mode: Receiver produces no pulses on any channel. Select in menu and wait 9 seconds.
• Hold Mode: Receiver outputs the last positions before signal loss. Select in menu and wait 9 seconds.
• Custom Mode: Pre-set required positions. Select Custom mode for the channel, then set failsafe for each channel and press Encoder to finish. Wait 9 seconds.

Notes:

• If failsafe is not set, the model will operate with the last working status, potentially causing damage.
• If failsafe is disabled on the RF module, the failsafe set on the receiver side will be applied.
• SBUS port does not support "No Pulses" mode; it always outputs signal. Use "Hold" or "Custom" for SBUS port.

FCC

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules.

CE

The product may be used freely in Germany, UK, Italy, Spain, Belgium, Netherlands, Portugal, Greece, Ireland, Denmark, Luxembourg, Austria, Finland, Sweden, Norway, Switzerland, France, and Iceland.

Flying Safety

Warning: To ensure safety, observe the following precautions:

• Have regular maintenance performed. While the TANDEM X20 PRO has non-volatile EEPROM memory, regular check-ups for wear and tear are recommended. Send your system to a FrSky Service Center annually during your non-flying season for a complete check-up and service.

Battery

Use a fully charged battery (DC 6.5~8.4V). A low battery can cause loss of control and a crash. Reset your transmitter's built-in timer at the start of a flying session and monitor usage duration. Ensure any separate receiver battery is fully charged before each flight.

Stop flying well before batteries become over-discharged. Do not rely solely on low battery warnings; always check transmitter and receiver batteries before each flight.

Where to Fly

Fly at recognized model airplane fields. Check with your local hobby dealer for model clubs and fields. Pay attention to flying field rules, spectators, wind direction, and obstacles. Be cautious near power lines, tall buildings, or communication facilities due to potential radio interference.

At the flying field

To prevent damage to radio gear, follow the proper power sequence:

1. Pull throttle stick to idle or disarm motor/engine.
2. Turn on transmitter power and wait for the home screen.
3. Confirm the correct model memory is selected.
4. Turn on receiver power.
5. Test all controls. If a servo operates abnormally, do not fly until the cause is determined.
6. Start your engine.
7. Complete a full range check.
8. After flying, bring the throttle stick to idle, engage kill switches, or disarm motor/engine.

Improper power-on/off sequence can damage servos, control surfaces, flood the engine, or cause unexpected engine start-up.

Ensure your transmitter cannot tip over. If it tips, the throttle stick may move, causing the engine to speed up or damaging the transmitter.

Maintain visual contact with your aircraft at all times. Avoid flying behind large objects like buildings or grain bins, as this may interrupt the radio frequency link and result in loss of control.

Do not grasp the transmitter's antenna during flight, as this can degrade transmission quality and lead to loss of control.

The strongest signal transmission is from the sides of the antenna. Do not point the antenna directly at the model. Adjust your flying style or antenna position if necessary.

Do not fly in the rain. Water or moisture can cause erratic operation or loss of control. Cover your transmitter with a plastic bag or waterproof barrier if flying in wet weather. Never fly if lightning is expected.

Updates

FrSky continuously adds features and improvements. Updating via USB Port or Micro SD card is free and easy. Visit the FrSky website's download section for the latest firmware updates and guides.