Linkpearls are basically radios, per Cid. He describes them exactly like real world two way radios (or cell phones) , only to give and say they use aether since the Warrior of Light is just staring blankly at him. Presumably, this means they are Garleanian in origin, being technology not magic. Whether the city states manufacture their own, or if the Ironworks makes them all and distributes them to the Grand Companies is unknown. They seem more advanced then the rest of Eorzean tech.

As for printing presses, all three city states have their own newspaper and reporters, which leads me to think they have presses. Presumably, they can't use scribes to hand write enough newspapers to the general populace.