"Please put down your weapon. You have twenty seconds to comply."
―ED-209 to Kinney.
The Enforcement Droid, Series 209, or ED-209, were a fully-automated series of peacekeeping machines created by Omni Consumer Products. The units were programmed for urban pacification, but OCP also negotiated contracts with the military for use in war.
The Future of Law Enforcement
"It gives me great pleasure to introduce you to the future of law enforcement: ED-209!"
During its first demonstration, ED-209 malfunctioned disastrously, blasting junior executive Mr. Kinney to death over a sustained period of time. Unable to stop the droid's rampage, Dr. McNamara and his fellow technicians struggled to gain control over their faulty robot, having to pull some sort of plug to finally shut it down. Because of the Kinney tragedy, the RoboCop program was given the green-light.
When RoboCop attempted to arrest Dick Jones (who was the collaborator of notorious mobster and alleged cop-killer Clarence Boddicker), Jones deployed ED-209. After taking severe hits, RoboCop escaped down a flight of stairs which stumped the droid, whose huge feet couldn't support it on the small steps, causing it to fall.
After its scuffle with RoboCop, Dick Jones took the opportunity to give the ED-209 project the green light, with RoboCop seemingly gone. An ED-209 was posted at the entrance of OCP, where it spotted an approaching RoboCop, who had reaffirmed his original identity as Alex Murphy and destroyed the robot with a Cobra Cannon from Clarence Boddicker (whom he'd just killed).
Attorney General Marcos later approved the 209 series for deployment in five American cities, including Detroit. Despite widespread complaints of malfunction, one of which getting its foot stuck in a manhole, the 209 series continually stayed in service even when OCP was taken over by the Kanemitsu Corporation. They were rarely seen on the streets and usually used as guards near OCP buildings.
The ED-209 was armed with three automatic cannons, two on the left platform, one on the right platform with an auto-shotgun and a rocket launcher capable of firing three rockets. It also had additional combat programming, enabling it to perform melee attack at closer ranges. Its speech center could synthesize human voices for peacekeeping matters, or animal-like sounds when injured or angry.
Despite its size and power, the ED-209's logic circuits were its weak-point. It could not process information as quickly as a human brain and bad design prevented it from successfully maneuvering an urban landscape.
ED-209 also suffered from a manual override weakness that allowed an unarmed and sufficiently skilled hacker to access its command system and take control of the mech. Nikko managed to achieve this by opening a compartment on the automaton's right leg which revealed three serial ports. She tactilely bypassed these ports and with her laptop was able to access the ED-209 command system interface. From there, she was able to issue commands directly, thereby taking full control of the bot.
An ED-209 appears in Mortal Kombat 11 as part of one of RoboCop's fatalities and his fatal blow. During both, it shoots the opponent with its machine guns.
Behind the scenes
The production team explains in the Criterion Collection featurettes that their approach to designing ED-209 was that OCP basically applied the same principles they used for modern automobile contracts to a military-grade walker-drone: OCP designed it to look impressive and flashy, but it really isn't very reliable "under the hood". Like a modern American car cranked out by vacuous corporate executives and lowest-bid design teams, they cut corners everywhere. Punctuating this, Dick Jones even outright states that it was irrelevant if ED-209 actually worked: it only had to outwardly look just impressive enough that it could dupe the rest of the board and potential buyers into accepting the development contract. It's the Ford Pinto of robot walker-drones. Some of the design features on ED-209 are supposed to accentuate the "style over substance" comparison to cheap company-designed low-bid automobiles, such as how it has metal grating around the front of the head like some modern SUV's - which apparently is only there to look "cool", and has no real function.
Highlighting that Jones cares more about contracts than how products are actually used, from a purely physical standpoint the ED-209 is ill-suited for urban pacification and police work let alone militaristic deployment: it has difficulty simply climbing stairs. The entire point of the ED-209 project was just as a backdoor to an even more lucrative military contract, and deploying them for police work was just a badly conceived test run. It was the equivalent of selling Abrams tanks or Apache helicopter gunships to Detroit, marketed as an actual replacement for patrols by mobile beat-cops and SWAT teams. This doesn't even begin to cover the severe programming shortfalls in the ED-209: even on a live battlefield, they'd probably end up shooting at units on their own side.
The irony of course is that Dick Jones ended up being hoisted by his own petard: he intentionally developed ED-209 as a cheap inferior product to sell like snake-oil to unsuspecting buyers, but then honestly thought he could rely on his flawed creation as his ace-in-the-hole against RoboCop. The only real OCP manufactured equipment that works as advertised.
In a twist of hilarious irony, at the beginning of the sequel, the defective product that is ED-209 had been; against better judgement, approved for widespread use anyway. Making Dick Jones offense at being sidestepped, superfluous.
The propsmasters in the Criterion Collection featurettes point out that they cheated during RoboCop's fight with ED-209 in Dick Jones office: it is obvious even by looking at the prop that the weapons-stub arms cannot be turned to shoot sideways, and thus, it was actually physically impossible for RoboCop push one of its arms to shoot off the other arm. He might have been able to do this if the other arm was partially damaged and hanging by wires, but in the next scene ED-209's remaining arm is still firmly attached.