Aurora is on version 7.1, available at the Aurora Forums.
Contact Erik on the forum for a wiki account.
Enemy ships with ECM degrade the range of your Missile Fire Controls (but not Active Sensors) by 10% x ECM level. A Fire Control sensor with a range of 30m km targeting a ship with ECM-2 would have only a range of 24m km.
Against Beam Fire Controls, 10% x ECM level is subtracted from the final hit chance.
ECM works automatically and does not need to be activated. It protects only the ship it is mounted on, though. Effects do not add up - only one ECM per ship is effective, although you can install more.
When targeting a ship with ECM you get notified about its strength.
An ECM component cannot be designed. As soon as you have finished the research, you'll find a new component available in the ship design window.
The effects of ECM can be offset by ECCM.
There is a research line that allows you to build Compact ECM systems that have the same effects but only a size of 1 HS (50 tons).
Note that as soon as you have researched ECM technology, you can equip missiles with it as well. A maximum of one Missile Size Point (MSP) can be assigned to ECM and makes the missile harder to target for enemy defensive weapons.
Researchable levels: 1-10
Size: 3 HS (150 tons)