@TimClose: Based on your description, the strike seems to be Normal Close or NC, therefore you need to wire the COM2/NC port based on QIG: http://www.grandstream.com/sites/default/files/Resources/GDS3710_QIG.pdf
The wiring diagram please refer to this one: http://www.grandstream.com/sites/default/files/Resources/GDS3710%20Connection%20%26%20Wiring%20Diagrams.pdf
You may need connect a protection diode in the circuit:
Also, I don’t know what is the current consumption of the strike, Please do NOT let strike to suck juice from GDS3710 and the strike has to have its own power source.
I don’t have the issue you experienced. From the description, I guess maybe you can check following things:
- Wiring and connection: Make sure the connection is good and wiring is correct.
- Make sure the strike using its own power source.
- Make sure the total length of the cable will not over 120 meters.
If you are using hosted IPPBX, please try comparing open door using direct IP call in the same LAN to rule out issue might involved by IPPBX.
Hope this helps. Thank you for using GDS3710.