Have a look at this Amazon review, click here, if it's the same type.
Note "If you want to connect wirelessy to your new network, by wLAN, you will have to go to the 'Settings' part of your device and seek out networks. Your Devolo network should then show. Selecting it, you will find that you require to submit a passwork before you can access the network. WHAT PASSWORD? The password you are looking for is the security ID which you will find on the back of the large plug! It consist of 4 groups of four letters. They are case sensitive and when you enter them you have to separate them using a - symbol. You only have to do this once. Previous Devolo kits came without a security set-up and relied on the buyer to set one up. This one comes with factory set security. Once up and running, this network provides a safe operating environment."