code stands for "Migration Authority Code"
and is issued by broadband providers when you want to change
"MAC" is used between broadband providers to help migrate
customers from one broadband provider to another. Mnay of the broadband
providers signed up to a code of practice to allow the MAC code
to help the end user.
is similar to the PUK code you have to request of you are changing
mobile telephone provider and want to keep the same telephone number.