Relays are the switching layer of security and low-voltage installations: relay modules that let an access-control panel fire a door strike, gate, or alarm, timer and sequencing relays that control when loads engage, and the multi-output boards that fan one trigger out to several devices. Every controlled door and gate has one of these somewhere in the path.
Specify by the electrical facts: the coil or trigger voltage must match the panel's output, the contacts must be rated for the load they switch - a magnetic lock and a gate motor are very different loads - and the form factor must fit the enclosure it joins. Sequencing and timing functions belong in the relay, not improvised in wiring. For installations with many doors, standardizing relay modules keeps panels serviceable by any technician who has seen one. COLAMCO supplies relay and power-control modules alongside the access-control and security systems they drive for business, government, and education facilities.