Unistim how to set loud ring

Version 11.25.1


I’m new to Asterisk and have just set up two Nortel i2001 phones. The basic functions work but I would like to know how I can set a loud ring. I have tried with ringvolume=3 and by manually increasing the volume on the phone while it rings, but the ring volume always goes back to the default. According to the Nortel i2001 manual there should be a an option when pressing the services key called ‘telephone options’ and the ringer volume should be in there, but I only have two options, codec and language.

Thanks in advance