The Pocket Programmer ($180) allows reading and writing of EPROMS, in which the program and data in OBD0 and OBDI Hondas are stored. When tuning, and making many rapid changes, the emulator is used. Although the emulator is not strictly necessary, it does speed the tuning process considerably and save dyno time.

Pocket Programmer Fix

A fix is available for all Pocket programmers sold prior to Sept 2002. Contact Xtronics to arrange a repair.

When the pocket programmer is first powered up it will default to a 25V output on a number of pins. the emulator requires 5 volts. Inserting the emulator at this point will cause several chips on the emulator to heat up and a power transistor to burn out in the pocket programmer. Removal of the case of the pocket programmer will help you rapidly identify any burned out component.

Until that repair is done the following procedure must be followed.

• Power up the laptop and pocket programmer without the emulator in place.
• Launch ROM Editor and open your desired ROM.
• Select download current tables ( The emulator should not be in place). This will drop the operating voltage from 25 to 5V.
• Insert the emulator.

It will now function as without overheating.

We also recommend that you do not leave the emulator powered on with the power to the ECU switched off for long a periods of time (10-15 minutes) as this may cause the emulator to overheat. The definition of overheat is when the chips are so hot they cannot be touched. Chips will get warm with normal usage.

Software updates and troubleshooting

Go to the Transtronics website for software updates. FAQs and troubleshooting the Pocket programmer are found here. Most commonly problem is when the Pocket Programmer will program the flash chips (at 5V) and not other chips. The FAQs tell you how to check the programming voltage.

Setting up the Transtronic Pocket programmer and emulator adaptor (no longer supported)

Plug the parallel cable into the PC and emulator adaptor into the top of the Pocket Programmer. Note that the position of the red stripe goes to pin 1 on the socket in the ECU. You must have a constant 9V supply to the emulator before switching on the PC.

Power Supply

The car lighter adapter must be rewired for a constant 12V if using the 12-9v adapter. This is because cranking the car cuts power to the lighter adaptor which erases the emulator memory (RAM). The result is an engine check light and the car running in limp mode.

Early pocket programmers used a negative center electrode. Later ones used a positive centre electrode. If the programmer does not work check the voltage level and polarity of your power supply. Plug in and power up the Pocket programmer. Some PCs require the Pocket programmer to be plugged in before booting Windows.

Open Hondata ROM editor and under File go to settings. Select Transtronics as the emulator type. If an error message says cannot open emulator, then remove the emulator adaptor from the top of the Pocket programmer and try again. Once the connection is established, then re-insert the emulator adaptor. This only needs to be done once. Early models are Rev 1B; all later versions sold since mid 2001 are Rev 2A. Selecting the wrong version means the car will only operate in limp home mode with a constant engine check light.


The Transtronics emulator adaptor is RAM based and allows you to make very quick changes to the ignition and fuelling values between dyno runs.


First you must download the entire ROM Ctrl+R which takes about 3 seconds under Windows 98. This must be done while the car is switched off. ROM Editor cannot verify if a download is successful, but verification is simple. Switch the ignition on. If the engine check light extinguishes and the light on the Hondata interface box is solid and non blinking, the download is successful.


If you are making changes to a particular fuel or ignition table Ctrl+E will download the changes in about 1/10th of a second from the table currently displayed. Any other changes will require the download of the entire ROM.


This emulator adaptor is not designed to accept changes while the car is running. Doing so will cause the engine to hesitate and sometimes trigger a check light. A fast laptop can sometimes download the current table without any problems, but this is not supported by Hondata. Once all your tuning changes have been made, remove the emulator adaptor and use the Pocket programming software to write a PROM or EPROM.


After tuning with the emulator, remove it and save the ROM file. Launch the Transtronics Pocket programming software, insert and program a blank chip then transfer the the ECU.

Make sure no chip is plugged into the programmer. Some chips require 25V to program; the Atmel AT29C256 requires 5 V. If you have inserted the Atmel Chip before you are ready to program you risk overheating and damaging it with 25V.


Launch the Windows Pocket Programming software (do not use the DOS version) Select the correct chip type from the list. If the list is not displayed. Press the button below no device to bring the list up. The Atmel 27c256 PROM is programmed at 12.5 V using the selection of 27c256.


Click the button load buffer and select the file you just saved from ROM Editor.

Insert the Atmel chip into the pocket programmer. Note the notch on the chip is uppermost, and that the chip is placed at the bottom of the socket.


Click the button . Programming takes about 30 seconds on a 500 Mhz Pentium.


Remove the chip, place it in the ECU and turn the key on to verify the engine check light goes off. For problems, consult the installation manual for troubleshooting proceedure.

 Map Tracing is not done through the emulator. It is done through datalogging and requires an interface box with datalogging capability.

Download the ROMEditor 2.5 manual for more information.