If you can use something, it's useful. Useful things are handy for whatever you're doing. If something is just what you need or you just find it helpful, then it's useful. A hammer is useful in building many things. Coasters are useful if you don't want a coffee table to get stains. College degrees are useful â or necessary â for many careers.
Where is the security key on a comcast modem located? The security key on a Comcast Modem is located next to the serial  number of the unit. Sometimes the serial number is the number used  as a security code if it is not printeâ¦d on the device. (MORE) 1 person found this useful.
Wi-Fi password (Network Security Key) serves to protect your wireless network and prevents from the unauthorized access to your PCs, laptops, tablets, phones, etc. In different operating systems it also can be called Wireless Security Key, Wireless Password and Network Security Key. It is a typical situation when you forget the security key for your Wi-Fi because everything has been working well for a long time. And suddenly you need to enter your Wi-Fi password again.