A MAC is a Migration Authorisation Code. (So “MAC code” or “MAC key” are incorrect terms).
OfCom rules (General Condition GC22) are that an ISP must issue a MAC within five working days of a request. The ISP must do this irrespective of any monetary or contractual dispute between the customer and the ISP. Such a dispute is not allowed to prevent the customer migrating to a different ISP, though of course the resolution of the dispute is still up to the customer and the ISP to negotiate.
The ISP should provide at least two ways of requesting a MAC, for example by phone, email, letter or ticket.
The idea is:
- you request a MAC from your ISP (they may or may not take that as the start of a notice period for billing purposes but that is irrelevant to the process);
- your ISP requests it from BT Openreach;
- BT Openreach supply it to your ISP who forward it to you;
- you supply it to your intended ISP who forward it to BT Openreach together with their order on Openreach to carry out the migration;
- BT Openreach carry out the migration and notify both the gaining and losing ISP on completion.
What this achieves is that BT Openreach know that the order from the new ISP is valid as it includes a MAC specifically relating to your line that the new ISP could only have obtained from you. Therefore eliminating slamming.
The MAC has nothing whatsoever to do do with your contract with the losing ISP. It merely allows the migration to take place irrespective of contractual disputes.
Note that - although BT Openreach are supposed to notify the losing ISP that the connection has been migrated elsewhere, for whatever reason this notification can fail to get to the losing ISP’s accounts/billing department.
So always make sure you notify your old ISP you have gone the day the migration completes. Preferably by some provable method not just a phone call, though with both my migrations I have just rung up and there has been no problem.
Before you start the MAC process make sure you have checked your contract Terms & Conditions regarding minimum contract periods, notice periods, and residual costs such as deferred joining; supplied modem and house move charges (if you have had a free one), and anything similar.
Also when requesting a MAC never use the words Cancel or Cease. Make sure it is clear that you intend to migrate then close your account. Cancel and Cease are often taken to mean cancel or cease your ADSL completely. That is a nuisance as you can be without for weeks, and expensive as you often have to pay connection charges.
Of course the whole thing falls down if you go to TalkTalk or Tiscali Full LLU, and probably Sky Full LLU as I assume that is now live, because no MAC is required. They just take your land-line off BT Wholesale and that's it!
Daft I call that last bit.