Many schematics are now available:
The electrical wiring diagrams of the base units (4D and HC) and for the 5 most common airpointer modules (O3, CO, SO2, NOx, H2S):
https://www.airpointer.tech/electrical-wiring-diagrams/
And the pneumatic diagrams, also for the base units and for the 5 most common airpointer modules (O3, CO, SO2, NOx, H2S):
https://www.airpointer.tech/pneumatics/
All these documents are in pdf format and can either be viewed online or downloaded.
Best regards,
Kevin Clarke.