We have a DTR-8D-1 Series-i Dterm set that is not behaving like other sets on our (SV8100) system.

On most sets pressing the up/down arrow keys when the phone is idle adjusts the LCD contrast (as expected).

On this particular set pressing the up/down arrow keys when the phone is idle adjusts the speaker volume.

I'm not able to find a way to change the LCD contrast on this device. Any thoughts?

So pressing the volume up/down while phone is idle should adjust contrast.

Yes, that's what I would expect, and our other phones behave that way, but this set shows "SPEAKER". I've confirmed that making changes at that point do indeed change the level of the speakerphone.

One thing to check. The contrast is not adjustable when the telephone has background music enabled. Try this.
To turn Background Music on or off:
1. Press idle Speaker.
2. Dial 725.
3. Press Speaker to hang up.

No wonder they call you a Guru! That did it (except it's 425 on our system, instead of 725).

Lol, thanks for the feedback AVboy. Glad to be of help.