Connecting a V2.0 Expansion Module to a D315 or D305 phone:
If you have an Expansion Module V2.0 (discontinued product), you can use it with the D315 and D305 phones by connecting it to the phone‘s EXT connector , but please note and make sure to heed the following warning:
Warning: Attach the module to the phone with one screw only, using the top hole. Using a screw in the
bottom hole will damage the phone‘s PCB!