Suggestion box

Hi,

We are a US-based organisation and have an office in the UK and some employees in a few countries of Europe. The management team in EMEA/Europe wants to set up a physical suggestions box in the UK office which has the largest population to have an employee voice on an on-going basis. I feel suggestion boxes are a thing of past and they end up being a complaints box. 

Any suggestions for alternatives?

Thanks

Shweta