Cable Instructions

If you wish to assemble your own exposure cable you will need to obtain the parts (all available at Tandy/Radio Shack) and have basic soldering skills. This section covers the serial cable portion for the 300D. Additional modification of a remote bulb cable is necessary for other models(ie 10D, D60, 1Ds, 1dMk2, etc)


  • One Resistor: 47Kohm
  • One transistor: 2N3904
  • One Diode: 1N4005
  • One 2.5 mm Stereo audio plug.
  • One 2 or 3 conductor wire (only 2 used)
  • One D-9 female serial connector

Threre are several other cable designs on the internet with pictures and instructions. Here are a few of them. We highly recomend the serial version as it is much more reliable and works with USB/Serial adapters for Legacy-free laptops.
Parallel & Serial cables on DSLR Focus Site
Modifying canon remotes for non-300D cameras

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