The ECU+ includes a number of uncommitted or unused inputs and outputs.
Included are five unused 0-5 volt analog inputs (three are currently available, the other two will be made available in a future firmware release). These can be tied to any 5 volt analog voltage and datalogged at full speed (25 samples per second). In general, these inputs are logged as a voltage, but the ECU+ also includes calibrations that interpret the voltage as an air-fuel ratio (if you hook up a wideband O2 sensor kit) or an exhaust gas temperature (if you hook up an inexpensive EGT adapter). Other calibrations are simple to do - e-mail firstname.lastname@example.org to have other calibrations added.
Four user-configurable 0-5 volt analog outputs are also included. These are useful for generating user-programmable fixed simulated sensor voltages, but are also available for other applications. In particular, the internal simulated front O2 signal uses one of these outputs. E-mail email@example.com if you have an application that could use one of these analog outputs.
In the digital domain, the ECU+ includes one uncommitted 5 volt digital input and two uncommitted 5 volt digital outputs. These are currently unused, but may be used in the future for some applications.
Lastly, the ECU+ includes 4 (3 for 1G DSM applications) drivers that can drive high current sources, like solenoids. These outputs are capable of driving solenoids in fixed or pulse width modulation (PWM) modes. Several upcoming features will use these.
The important point to remember is that unlike other engine management systems (or ROM tuning systems that alter the stock ECU and thus can never add more inputs or outputs), the ECU+ isn't maxxed out when you get it. Instead, there's lots of room for expansion and additional features with the ECU+'s hardware.