Testo Thermal Camera Hidden Menu access ?

[Fraser]

Does anyone know how to access the hidden menu's on a 800 series Testo thermal camera please  ?
My specific model is the 880-1 built in 2009. Response by Personal Message if preferred.

The camera is also sold under the Electrophysics (Sofridar) brand with the same model number.

Any other model 'secrets' also welcomed 

Many Thanks

Aurora

[ixfd64]

I don't own a Testo camera, but I'm also interested in what could come out of this.