This is Stu's previous post, i shamelessly stole it cuz its such a good explanation
Ok, here goes...
Pectel, are a company that (i believe) formed in teh 80s and soon became masters of the Weber marelli Ecu systems and their affiliated soft/hardware. Back in the day, the cosworth was fast becoming the engine of choice for fast road and motorsport but the hurdle most couldnt overcome, was making the ecu's run teh modified engines PROPERLY.
Pectel designed a system that would allow people to map it easily, with a DOS based mapping interface. They perfected the mapping and run software and it worked flawlessly in the ecu. The run software like any other, is the "Opertaing System" that runs the hardware that you know as an ECU. PC buffs can liken a chips software to their motherboards BIOS.
This is where Pectel differs from a company like myself, we will make the existing run program do what we want it to do by adjusting its maps and calibrations and then burn the modded program back to a chip, Pectel cleverly designed a whole NEW run software system that bore no resemblance to teh original at all and could be adjusted map by map using the mapping software they supplied to their customers(Pc buffs.. a bit like teh difference between, Award and AMI bios. Both totally different, but with the same end result)
What pectel then had to do was protect all their hard work:
The mapping software (Called IEMS for L1 = 8 and IEMS P8 for P8) was simply that, a software program that would be ripped off in no time. They programmed a dongle for the parallel port and that would ward of most thieves, but still made it a one time only purchase, not exactly business idea of the year, so what they did then was, back in its day, quite unique...
They altered the mapping softwares "Save" program so that when you had finished your maps, and saved them ready for burning to a new chip, the program "Encrypted" the file so it WOULD NOT run in a marelli ecu.
How did you get it to run?
You bought a "DE ENCRYPTION" or "PROTECTION" board that would translate the encrypted message from Chip to ECU. This hardware was copyrighted and only available through Pectel. Now they had a viable product and everytime someone made a new performance chip with thier software, even if they had ripped it off, they had to purchase some hardware from Pectel before it would run an engine.