Sub.net has a maximum of 12 analogue channels which may be voltages, currents or transducer inputs. A series of pluggable input modules determine the type of inputs. For applications that require more channels any number of systems may be interconnected using a cross triggering scheme. This uses the triggered status output relay and a contact input of each sub.net.

If any of the interconnected systems detects an out of limits condition then it will trigger an event report. At the point the trigger is detected the status relay is asserted and this will cause all the other systems to also generate event reports. If another system detects a trigger during the recording time then it will also assert its own triggered status relay and extend the recording times of all the systems if necessary.

Since the contact input is common to all the event reports this may be used to synchronise the data in each record.