How do I open BT Synergy 5500 Handset?

Ok, from the horses mouth!!! The "Correct" way to unlock as the arrogant chappie from India said is to press the top left key briefly and in within TWO seconds press the unlock key briefly. Took me Three attempts but to my surprise it actually worked! You just have to get your timing right and remember press the keys BRIEFLY... Damn the man from India was right!!!!!

Staceyboy
October 2011

After some perseverance I have found the answer.
1. Remove battery cover & batteries
2. Pry off side pieces. Theses are partly glued on so much care is needed. (Run a very thin screwdriver up the side along the edge.)
3. Pry off black front cover.

All should be done with much care as you might damage the casing.

Alan
June 2011