when a call rings in the DSS lamps of the extensions that ring light up. I've disabled this before , but can't seem to find it this time . Can anyone help?

I've always considered that a normal system feature. Maybe you're thinking of disabling a message waiting (green) blinking light on the DSS.

No, It could on DSS keys that are programed on the keyset. All phones that are programed to ring, the DSS keys on the attendent phone light up on the ring cycle. I have disabled this before. Must be age setting in. They say first your eyes and then your mind.

Try programming the keys as Call Coverage-no ring, instead of DSS keys. I think that might solve your issue. You still get the DSS 'functionality' without some of the other features. With older software, I always used this when the attendant didn't want to see the MWL for the DSS extensions.

Let try setting 04.70.02 to "Disable".
Hope this help!