Mike Shellim June 2003
Updated 13 Sept 2011


Part of the fun of reviewing radios is trying to eak out all the features - and occasionally bugs - in a new transmitter. Not so much fun, however, is having to fiddle with servos and batteries all the time!


With this in mind, I have made a little gizmo for exploring a transmitter's programming on the PC screen.

The heart of the system is an interface which goes between the tx DSC (trainer) socket and a Windows PC.


The interface is based on a PIC 16F628  microcontroller. The PIC monitors the trainer sigmal from the transmitter. In most systems, this is a series of short (~300 microsecond) negative going spikes. The pulse intervals are encoded into 3-character hex strings and sent to the PC over a serial link.

The PIC firmware is written in assembly language.

PC Software

A Visual Basic program running on the PC monitors the serial signal from the interface, and decodes the pulse intervals.

Supported Tx's

The system has been tested with the following tx's


Version 1 (left): The picture above shows the EPROM programmer and Lab X2 dev board. 

Version 2 (left). This is on a board 70mm x 60mm.

Version 3 is smaller still and uses just 9 components (no picture available)


All shots show "Bargraph" display mode

Switch on the Tx. Note that the servo's are not quite centred, so...

Set a new baseline. No movement until...

The Aileron stick is moved. The wing servos (along the top line) respond.
So do the V-tail servos, due to combi mix.


This is the "Mark" menu for setting a new baseline.

The Options menu selects MPX or Futaba/JR/Hitec neutrals.

You can select a number of viewing options.


The system is under development