Counter-hit setups and frame traps aren’t really the same thing (eg. “all kittens are cats but all cats aren’t necessarily kittens”). The idea of Frame Traps mainly comes from games like Tekken and Soul Calibur. SFIV is basically the only game where people consider counter-hit setups and frame traps to be the same thing.
A frame trap is a sequence of 2 moves separated by a gap that is smaller than the opponent’s fastest normal move that can hit at that distance. eg. Blanka’s lp electricity into sweep is a frame trap because even though 3f and 4f moves would theoretically beat the sweep, they don’t have enough range so the opponent is forced to use something like cr.hk, which will lose to Blanka’s sweep.
If you have a sequence of moves with a 3f gap in between them, and your opponent has a 3f jab, it’s not really a true frame trap. However, 3f gaps are legit vs chars whose main crouch teching options result in 4f normals (eg. shotos). And because it’s such a common thing to do, people just call them frame traps for the sake of brevity.
“Frame” also just refers to the startup, not the invincibility or other stuff like that. So doing stuff like DP after a blocked move is not a frame trap. Using Rose’s st.mk in strings to blow up throws is not a frame trap. Neither is using Viper’s lk Burn Kick. They rely more on things like invincibility frames than startup.
Another class of setup is where you rely on the property of a moves’ hitboxes to beat the opponent’s options. eg. If you have a move that has a hurtbox situated relatively far behind it’s hitbox, you can use it in certain situations to beat your opponent’s options even if they use moves that startup faster. Note that this does not score a counter-hit, and it’s not a frame trap.
There’s no real harm in calling certain things frame traps even though they aren’t. Language evolves over time and people just learn to accept it eg. saying “vortex” instead of 3+ way Okizeme, or how the meaning of “abare” changes between 2D and 3D games. You do lose some expressiveness though. “Frame trap” implies something about the nature of the sequence of moves. There’s nothing inherent about manually delaying two moves in order to bait something, because the length of the delay is entirely up to the player. On the other hand if someone tells you X followed by Y against a certain character is a frame trap, then technically it means beat any normal (with enough range to hit) that the opponent tries to do. This allows you to infer the frame data. Still, it’s no real biggie.
Re: Delayed crouch tech
"Late crouch tech" is actually option select tech, from a crouching position. Originally OS Tech referred to delaying a tech until the 8 or 9th frame so that you’re able to block and tech (that’s essentially the OS). This is the original delayed crouch tech guide (Japanese, with video examples and frame diagrams):
http://translate.google.com/translate?hl=en&rurl=translate.google.com&sl=ja&tl=en&u=http://color-k32.sblo.jp/article/34419943.html
He also gives examples of counter-hit setups to beat delayed crouch tech, and OS options for the defender.
There are of course other forms of OS Tech eg. f, d, df + lk + lp: Techs throws, or performs a DP - useful after empty jumps. Delayed standing tech will block true frame traps, tech throws, and throw opponents out of counter-hit setups (if they’re in range). It loses to step back, cr.mk/hk.
One thing that’s worth investigating IMO is creating frame traps off meaty situations. Even if a series of moves isn’t a “true” frame trap, you can turn it into one by landing the first move meaty on the opponent’s wakeup. So in theory: Ken’s st.mk has 5 active frames, and is -2 on block. If you can find a setup that will cause it to hit on the last active frame, you can basically turn it into a +2 on block move. Follow up with cr.mk for a true frame trap (doubles as a combo on hit). It’s like scoring a max range f.mk, but it leaves you closer to the opponent which makes them more likely to press buttons. I guess most Ken players already know about this one though.
