I was having a problem with my BT Synergy 2110, go to www.google.co.uk and type in Synergy 2110 manual. I got one straight away, it's 33 pages long mind!!
Kellie
March 2006
need information how to obtain instruction information for bt 2110 telephone
georgehugman
September 2005
You'll find it online here:-
http://www.bt.com/userguides/downloads/synergy2110.pdf