Once We Lived in Nanjing

Wednesday.

Wang Ning, relying on his bottomless connections and even more bottomless cheek, managed to get a second-hand GR3188 relay station from the HAM community in Nanjing City. He had Xiao Zhu deliver it to the headquarters that very same day. The base station used in the relay was the same as the one Ban Xia found, both being Motorola GM300 models.

That night, when Bai Yang got home from school, the living room had turned into a large second-hand electronic scrap collection station. Old Wang and Dad were squatting amidst scattered electronic components and tools such as screwdrivers, wrenches, and screwdrivers, surrounding the Icom725 radio and the GR3188 analog relay, looking exactly like two computer repairmen who made house calls.

"Give me the schematic. I need to find this COR OUT interface..."

"Where's the multimeter? Did you bring a multimeter? I asked Xiao Zhu to bring one over."

"Broken. Do we need to use a soldering iron to wire this up? Can you find a soldering iron over there? And what about the flux?"

"Worry about what? Can't find a soldering iron in all of Nanjing City?"

"What a crappy relay, where was it used before? Why can't it be cleaned? Touch it and your hand's all black, filthy as hell."

"Rag!"

Bai Yang walked into his room, tossed his school bag on the bed, and his mom, sitting on her bed browsing her phone, lifted her head and called out, "Yang! Your food's in the pot in the kitchen!"

"Got it."

Bai Yang went into the kitchen, lifted the lid of the pot, which contained lukewarm noodles.

He took his bowl of food, leisurely went back to the living room, and squatted next to Wang Ning and Bai Zhen. The two middle-aged men were busy tearing apart the relay station, removing the cooling fan to reveal all its ports and the tangled complex cables.

"So complicated." Bai Yang slurped his food, "Can she handle it?"

"Actually, it's not complicated at all." Wang Ning was focused on screwing, "As long as you understand the internal technical logic, the operation is very simple... Shit, it broke!"

"You know communication networks are divided into seven layers, right?" Bai Zhen spoke, "The bottom layer is hardware, the top layer is protocols. In fact, it's the superstructure that's important. As long as you can understand the logic behind the encoding, you can manage the hardware. For instance, if you have the ability to transmit images, whether you use a 4K LCD or an old black and white TV set, you can still watch 'Avatar'. The only difference is the image quality... Shit, it broke again!"

"The principle of this thing is very simple. I've talked to you about it before. It's just relay control, flip and receive. You use a handheld radio to remotely contact the relay, and you can achieve the effect of a mobile phone." Wang Ning forcefully pulled out a small green printed circuit board from the relay station, about the size of a thumbnail, connected to a thin white wire and lifted it for Bai Yang to see, "Here, look, it's this thing. Later, you use it to connect the relay with the control unit. Just find the right port and pins, and it can do a lot of work."

"Nearly all the cables in this room are a single copper core, but they transmit different types of signals." Bai Zhen pointed around, "The same hardware basis, different network protocols."

"So..." Bai Yang hesitated, "We still have to teach her the OSI seven-layer model?"

"The best is combining theory with practice, and teaching her to understand the TCP/IP protocol would also work." Wang Ning nodded.

"But even I don't understand it." Bai Yang spoke with noodles in his mouth, his words unclear, "How can I possibly teach others?"

"How can you not understand?" Wang Ning glanced at him, a strange look in his eyes, "Isn't that common knowledge?"

"How can you not understand?" Bai Zhen also glanced at him, a strange look in his eyes, "Isn't that common knowledge?"

Bai Yang held back for a moment, then retaliated angrily:

"How come you two couldn't get into college? Isn't that just a matter of having hands?"

...

...

...

"Hmm... BG4MXH, this sounds so difficult."

Ban Xia was having some trouble.

She had paper and pen ready on her table, prepared to be a diligent student who listens attentively, yet the other person started with a barrage of network protocol acronyms in English and hit her with a dizzying array of terms, like TCP, UDP, ICMP, this P and that P, comparable to a student who had just mastered arithmetic starting to read Landau's ten volumes.

"BG4MXH, I don't understand at all, this stuff is so hard, do I really have to learn it?"

"That's theory, OVER."

"What's the use of theory?"

"Theory is useless, OVER."

"So..." Ban Xia cautiously asked, "If it's useless, can we not learn it?"

"You can skip it, OVER."

Bai Yang was straightforward.

Ban Xia cheered on the other end, along with the sound of a pen being thrown.

As someone living in a post-apocalyptic era, for the first time in her life, she experienced the immense joy of an exam being suddenly canceled.

What a precious experience this was.

"Miss, let me tell you, anyone who forces you to learn complex theoretical knowledge is a devil. Is there anything more useless in this world than a conic section, a quadratic function, or a sequence set? No! And if there has to be something, it would be calculating how many circles a charged particle can turn in an electric and magnetic field... Mathematics can go to hell! Physics can go to hell! Mathematics and Physics can meet their doom!"

"Mathematics can go to hell! Physics can go to hell!" Ban Xia also shouted, "Let Mathematics and Physics go haunt someone else!"

"Math and Physics exams can go to hell!" Bai Yang chanted, "Down with the three big mountains of Math, Physics, and Chemistry!"

"Down with the three big mountains of Math, Physics, and Chemistry!"

"Liberate senior high students worldwide!"

"Liberate senior high students worldwide!"

"Get to the real work quickly," the old man knocked on the door from outside, "or else if all the senior high students worldwide die out, who will you liberate?"

Ban Xia opened the casing of the GR3188 relay station; under Bai Yang's guidance, she first needed to get a clear understanding of the relay station's structure. The structure of the GR3188 analog relay station was quite simple; plainly speaking, it was big, black, and unwieldy. Opening the back cover revealed cooling fans and messy cables. Removing the fans, one could see the rear connectors of the internal base stations. The fundamental components of the GR3188 consisted of two base stations, as well as a relay control board and a duplexer, stacked on top of each other from top to bottom.

Most parts of the relay station didn't need any changes by Ban Xia. As Wang Ning put it, the relay station's hardware itself was sufficient to support your needs. Just like how a color LCD screen can play movies, so can a black-and-white TV. Ban Xia's task was to find the right interfaces and plug the correct plugs into the right sockets, a trick that only experienced pros knew how to execute, thus requiring the full guidance of Wang Ning and Bai Zhen.

Bai Yang was relieved that building a remote control system did not involve very delicate operations. There was no need for Ban Xia to wield a soldering iron to solder PCB boards; otherwise, that would really be like forcing a square peg into a round hole.

"Miss, now tell me what you see, OVER." Bai Yang asked, holding the microphone.

"Um..." The girl was wearing headphones, with the GR3188 relay station on the desk in front of her. Ban Xia tilted her head and peered into the chassis, "I see lots of wires, red ones, black ones, and white ones, thick and thin, all in a mess."

"What else is there? What else is inside the chassis? OVER."

"Inside the chassis, there are two butts of amateur radio stations stacked on top of each other, screwed down inside the chassis and unremovable," Ban Xia continued to reply. "There are several thick wires plugged into the butts of the radio stations."

"Don't mess with those. What else? OVER."

"Also, there's a black metal box at the very bottom inside the chassis, with no openings, sealed."

"Don't touch that either," Bai Yang said, "Miss, listen carefully. I'm going to tell you which interfaces we're going to use and which we won't, OVER."

"Okay, I'm listening," Ban Xia nodded.

"First, count how many wires are plugged into the butts of the two base stations," Bai Yang instructed, "Check how many sockets there are, OVER."

"One... Two, three..." the girl started counting, "Six wires in total, six wires, with each radio station having three. There's one thickest black wire, with a wide flat socket, and another black wire with a round socket. The last one is white, the thinnest, and this wire is connected to a black square plastic piece plugged into the butt of the base station..."

"That's a green plastic piece, OVER." Bai Yang said.

"Green?" Ban Xia widened her eyes, "No, it looks black to me."

"That's because it's too dirty with dust," Bai Yang explained, "That piece of plastic can be pulled out. Take it out and wipe it off, OVER."

Moments later, a shout of surprise came through the headphones.

"Really! It's green! And there's a circuit on it!"

"Correct, that's a PCB board, or a printed circuit board, which is always green," Bai Yang explained, "We will need to use this interface, this thin white wire. It will connect the relay station to Unit 725. Do you understand? OVER."

Ban Xia nodded, somewhat understanding.

"Got it."

"BG4MXH once said that going to class is learning, learning means going to class, and the ordeal of attending classes is something everyone has to go through while growing up. Every child, upon reaching the age of seven, is forced into the prison and concentration camp called school, losing their freedom, at least until they are twenty-two years old and can finally be liberated. Now, as Ban Xia looked at the relay station that looked like a black box in front of her, the thought of having to understand it made her realize that not everything in the world before the apocalypse was good.

Not going to school, that is truly good."