Everything so far has treated the interlock as a pair — this licensee, that firm. On a real job it is more specific than that, because the rules attach each licensed act to a particular firm’s certificate number. 28 TAC § 34.616 says that the licensee responsible for the planning of a system, including monitoring equipment, must be licensed under the Alarm Certificate of Registration number of the registered firm responsible for the planning. It then says the certifying licensee — the one licensed under the certificate number of the firm responsible for the INSTALLATION — must be present for the final acceptance test before certification, meaning the test performed at the end of an installation before the system is certified, which Chapter 8 takes up. Two roles, two firms named separately, and the rule is careful to say which certificate each one answers to.

That care exists because the same rule allows something a reader may not expect: the registered firm responsible for planning the system can be a different firm from the one responsible for installing it. This is common on larger construction work and it is expressly permitted. What it means in practice is that the question “is this job covered?” has no single answer — the planning is covered by one firm’s certificate through its superintendent, and the installation and its certification by another firm’s, through the licensee who has to be there for the final acceptance test. Neither firm’s certificate covers the other’s part of the work.

The same logic reaches the labels a job leaves behind. Under 28 TAC § 34.616, the licensee attaching a label must be licensed under the certificate number of the primary registered firm. A label is a signed statement about work, so the rule ties it to the firm that answers for that work rather than to whoever happens to be on site with a pad of labels. This is the practical end of the interlock: what a registered firm may take on is bounded by the licenses its people hold, and what a licensee may do on a given day is bounded by which registered firm’s certificate number they are working under. Chapter 4 sets out what each license class reaches; Chapter 9 covers the labels themselves.