What is a tower
A tower is a small, several story structure, usually just outside a facility. They all have a CC, 2 doors each on their roof and ground floor with IFF locks, and a spawn room with tubes, lockers, and equipment terminals. There are three types. Air towers feature two landing pads that Repair/refit aircraft, and two wall turrets. Gun towers feature two wall turrets. Watch towers have no guns, but are five stories and feature a middle “balcony”.
Why is it important
Any veteran will tell you that holding a facilties tower is a key point to taking the facility. They provide a spawn location near an enemy facility, much like an AMS. A tower, though in a fixed location at the edge of a facilites SOI, has several advantages over an AMS. First off, it has it's own SOI, meaning enemy's can't drop certain CE devices just outside the door. Also, since it's a structure, it can't be destroyed, and protects infantry from OSs and vehicles. One of it's biggest advantages, however, is that it allows access to MAX suits, a feature that the AMS is lacking.
First and foremost, CE is key. Place boomers on the inside door, one each, and an alarm near the CC. Heavily mine the outside. Spits and alarms aren’t too useful outside, as vehicles will probably show up early, and then easily destroy them, without taking much damage. Mines, however, will wreak havoc on them. A very deadly combo is a combination of Disruptor Mines and AV. The mines make it so vehicles can't fire their weapons, leaving them open to a salvo of AV rockets. MAXs should set up just inside the door, on the stairs towards the CC. If the people using them have DL, they should activate it. Once the enemy is inside, push hard from the spawn room, and head either to the CC, or keep pushing the enemy outside. If you can bring in vehicles from an outside source, do so, or else enemy vehicles will seal you in. Once they reach the spawn room, try your best to kill them, calling for some CC defence to help (keeping in mind it's probably also under siege). Repair the spawn tubes and terminals as necessary. Also keep an eye out for airdrops on the roof. SA will be really useful in shoving back anyone who comes through the main floor. Just sit on the lower and upper landings, aim at the ground floor, and fire (after making sure it’s clear of friendlies). Standard weaponry is all that’s needed for taking out air droppers. However, despite this, once the tower has troops inside, it’s near impossible to beat them back without outside support. in a heavily forested area, a TRAP may be able to bottleneck people, but in an open space the high influence radius makes it little more then a target. Cerberus turrets placed on the roof/ground may help prevent mossies campers, but will do little to stop droppers and ground forces. Also keep an eye out for phantasm, who can easily drop half a squad onto your roof with no warning. Shadow turrets, however, can make a heavily defended roof appear an easy target, perfect for ambushes on droppers.
Attacking is quite a bit easier. First, bring in vehicles to take out spits and enemy troops, as well as other vehicles. Once you have the outside secured, then set up a vehicle perimeter, and start firing inside once the doors open (until your own side starts going through, of course). If you have the means, drop on top, and attack the CC, forcing the defenders to guard from two angles. Once inside the main floor, try to set up some people to keep the enemy trapped in the basement (MAX’s and SA is really useful), but send the main force to the CC. If you can get down to the basement, take out the tubes. Try not to have everyone run downstairs, lest the respawned troops escape back to the CC. As you kill people guarding the CC, you can hopefully keep them trapped downstairs, unable to do anything until the tower is yours, leaving them nowhere to spawn, and trapped in a pain field. Like mentioned in the defense section, once you hold the outside, it’s going to be hard for them to take it back, though you should keep an eye open for outside attacks, which are your biggest threat. If your on the outer part of an facilities SOI, or attacking a lone tower, a OMFT can help in keeping people contained, especially in a lone tower, where both doors can be covered. An Aegis Shield Generator can also provide a good hiding place for unmanned vehicles, so they don't fire on them if they start to push out, and soldiers can easily get in them and push them back in. Someone with Assault Engineering can also place spitfires just outside the doors, making for a nasty surprise when defenders try to push out.