Below is a list of the different support you can call in and how long it will take to arrive.

30mm Strafe Run:
27 Seconds till strafe begin.

Grenade Drones:
30 Seconds until payload detonation.

IED Drone:
Spawns in 30 seconds, seeks out target.

Rocket Barrage:
35 Seconds until barrage begin.

Explosive Artillery:
48 Seconds until first shell hits.

Minigun Support:
40 Seconds to arrive, stays for 30.

Gunship Support:
40 seconds to arrive, stays for 20.

Smoke:
47 Seconds until first shell hits.

Chemical Mortar:
46 Seconds until first shell hits.