Thanks for the info and all the ideas guys. I found some info
here and emailed them for further details. The trigger output is a 2.5mm audio jack similar to the TC-80N3. the various camera specific cables also look very familiar so I'm confident that the voltage output will be close to what a standard intervalometer would provide. I know what to look for and can work out the wiring. The only unknown at this stage is timing. I don't know how much lag there is between the IR firing and the NEX-5 shutter release. I guess triggering within the ball park is better than nothing but I would assume it is as fast as a direct cable connection?