WEBVTT - TechStuff Classic: How USB Ports Work 0:00:04.440 --> 0:00:12.600 Welcome to tech Stuff, a production from iHeartRadio. Hey there, 0:00:12.600 --> 0:00:16.239 and welcome to tech Stuff. I'm your host, Jonathan Strickland. 0:00:16.320 --> 0:00:19.720 I'm an executive producer with iHeartRadio and how the tech 0:00:19.760 --> 0:00:23.680 are you? It is time for a tech stuff classics episode. 0:00:23.680 --> 0:00:28.680 In this episode originally published on April twenty first, twenty seventeen, 0:00:29.080 --> 0:00:34.680 it is titled how USB ports Work? And Yeah, you know, 0:00:35.560 --> 0:00:39.120 once upon a time, the USB was a novelty. It 0:00:39.159 --> 0:00:44.040 was a new feature on hardware like laptops and such, 0:00:45.240 --> 0:00:49.160 and it caused a bit of confusion when it first 0:00:49.200 --> 0:00:51.839 came out. People weren't used to it. They were used 0:00:51.840 --> 0:00:54.600 to things like proprietary ports. So we're gonna listen to 0:00:54.640 --> 0:00:58.640 this classics episode about USB ports. I hope you enjoy. 0:01:00.000 --> 0:01:05.000 We'll find these ports on computers, smartphones, digital cameras, scanners, printers, 0:01:05.080 --> 0:01:08.120 and tons of other electronic devices. So what are they, 0:01:08.240 --> 0:01:11.240 who invented them? And how do they work? You know, 0:01:11.560 --> 0:01:16.679 your standard tech stuff type episode. Well, you could just 0:01:16.760 --> 0:01:19.400 go and read the specification for USB if you really 0:01:19.440 --> 0:01:22.000 wanted to, and that would give you all the information 0:01:22.080 --> 0:01:27.119 you need and more. For example, the specification for USB 0:01:27.240 --> 0:01:29.840 two point zero is a mere six hundred and fifty 0:01:30.000 --> 0:01:34.679 pages long seems a bit excessive to me, so let's 0:01:34.920 --> 0:01:38.880 break down the topic tech stuff style. So first, let's 0:01:38.920 --> 0:01:42.800 talk about what a bus is. In computer terms, a 0:01:42.840 --> 0:01:46.120 bus is essentially a conduit for data. Think of it 0:01:46.200 --> 0:01:49.520 like a hallway that data can pass through. It's a 0:01:49.520 --> 0:01:53.760 communication pathway that lets different components within a computer or 0:01:54.120 --> 0:01:58.040 two different devices send data back and forth between each other. 0:01:58.880 --> 0:02:03.360 That means some buses are internal and facilitate communication within 0:02:03.480 --> 0:02:07.520 a single device. Other buses are external and allow for 0:02:07.560 --> 0:02:12.080 the communication of different components like a smartphone to a 0:02:12.200 --> 0:02:16.000 computer for example. So inside a computer, you would have 0:02:16.040 --> 0:02:20.480 a bus connecting components like the microprocessor and a memory 0:02:20.520 --> 0:02:24.400 storage device like a hard drive. So the computer's operating 0:02:24.440 --> 0:02:28.040 memory and CPU tend to be very closely tied together, 0:02:28.240 --> 0:02:31.240 as in its operating memory like the random access memory. 0:02:31.639 --> 0:02:35.440 That and the CPU are usually real tight. But they 0:02:35.440 --> 0:02:37.880 still have a bus, and it's usually called the system 0:02:37.960 --> 0:02:42.000 bus that connects the two. And just as microprocessors and 0:02:42.120 --> 0:02:46.000 memory have improved over time, so if buses, they've improved 0:02:46.040 --> 0:02:49.560 to allow more data to pass through at a single time. Now, 0:02:49.600 --> 0:02:53.120 keep in mind information is traveling at pretty much the 0:02:53.200 --> 0:02:55.839 same speed, you know, more or less the speed of light. 0:02:57.160 --> 0:03:00.080 It's not quite the same, but for the purposes of 0:03:00.280 --> 0:03:04.200 our argument, it works just fine. So really the question 0:03:04.320 --> 0:03:08.400 is how much data can you move through the bus simultaneously? 0:03:09.240 --> 0:03:12.480 Or if we wanted to use a metaphor, imagine that 0:03:12.639 --> 0:03:17.040 you have an eye dropper and your friend has a bucket, 0:03:17.480 --> 0:03:21.320 and you're each taking water from one puddle and walking 0:03:21.360 --> 0:03:25.240 across a field at the same speed and depositing that 0:03:25.320 --> 0:03:28.520 water into a little dip in the other end of 0:03:28.560 --> 0:03:31.520 the field that's going to become the new puddle. So 0:03:31.560 --> 0:03:34.400 you're just relocating water from one puddle to the other. 0:03:34.800 --> 0:03:38.360 Now you're walking at the same speed, so it's not 0:03:38.400 --> 0:03:40.800 that your friend is going faster than you are, but 0:03:40.840 --> 0:03:44.840 they can carry more water per trip, so they're delivering 0:03:44.920 --> 0:03:48.360 more water every time they make this trip, and even 0:03:48.400 --> 0:03:50.400 though you're both going the same speed. This is why 0:03:50.640 --> 0:03:54.840 I get a little antsy about data speeds, because it's 0:03:54.880 --> 0:03:57.200 not really so much about speed. It's more about the 0:03:57.240 --> 0:04:01.000 amount of data you can carry at a time. That's 0:04:01.120 --> 0:04:03.520 kind of what I'm getting at. So if you hear 0:04:03.640 --> 0:04:08.080 like this computer sends data faster than that computer, the 0:04:08.120 --> 0:04:10.400 information is still traveling at more or less the same 0:04:10.440 --> 0:04:15.640 speed depending upon what medium they're using. But it all 0:04:16.160 --> 0:04:19.480 is down to how much information can pass through at 0:04:19.520 --> 0:04:23.360 any given time. Now, there are also buses that allow 0:04:23.480 --> 0:04:27.919 data transfers with sources that are external to the computer. Again, 0:04:28.000 --> 0:04:30.760 the smartphone is a great example, or a digital camera, 0:04:30.960 --> 0:04:35.360 anything like that. The buses facilitate the data transfer, which 0:04:35.400 --> 0:04:38.480 typically happens over a cable, and there are plenty ways 0:04:38.520 --> 0:04:42.360 to transmit data wirelessly, but we're just going to concentrate 0:04:42.400 --> 0:04:46.400 on cables and tethered peripherals today because that's what USB 0:04:46.960 --> 0:04:49.559 works with, right, That's the protocol is that you're using 0:04:49.560 --> 0:04:53.960 physical connections. In other episodes, i'll talk about stuff like 0:04:54.600 --> 0:05:00.240 Wi Fi or Bluetooth or other methods of transferring data around. Now, 0:05:00.279 --> 0:05:03.279 before USB ports became a standard way to connect various 0:05:03.320 --> 0:05:06.800 components to a computer, we had to rely on other 0:05:06.960 --> 0:05:12.080 types of ports, like parallel and serial ports. Serial parts 0:05:12.240 --> 0:05:18.120 are se r L ports, not not serial like Captain crunch. 0:05:18.960 --> 0:05:22.800 They're basic computer connections. They send bytes of data one 0:05:23.080 --> 0:05:26.919 bit at a time. So, in case you don't remember 0:05:27.000 --> 0:05:31.800 basic computer lingo, a byte is eight bits and a 0:05:31.839 --> 0:05:36.120 bit is a single unit of information in computer speech, 0:05:36.160 --> 0:05:38.920 it's either a zero or a one, which is kind 0:05:38.960 --> 0:05:42.440 of like an off on switch. So a byte is 0:05:42.640 --> 0:05:49.200 eight of these collected together. Serial ports send information one 0:05:49.520 --> 0:05:52.240 bit at a time one zero or one to one, 0:05:53.400 --> 0:05:56.599 and then does a whole sequence of those Serial parts 0:05:56.640 --> 0:06:00.800 had either nine or twenty five pins. The nine pin 0:06:00.880 --> 0:06:04.320 connector was a standard for modems. We're talking about the 0:06:04.320 --> 0:06:06.880 old dial up modems that would connect to your phone 0:06:06.920 --> 0:06:11.000 line and allow your computer to communicate with the outside world. 0:06:11.440 --> 0:06:13.159 If you don't know what a dial up modem is, 0:06:14.560 --> 0:06:18.279 you know, ask your parents. Each pen was designed to 0:06:18.320 --> 0:06:21.480 allow for communication between the computer and the modem in 0:06:21.560 --> 0:06:24.200 some way. The twenty five pen connector was meant to 0:06:24.200 --> 0:06:26.960 become a new standard, but was so much larger than 0:06:26.960 --> 0:06:29.560 the nine pen connectors that it was a bit hamstrung 0:06:29.600 --> 0:06:32.080 from the start. Not everyone adopted it. In fact, a 0:06:32.080 --> 0:06:35.560 lot of manufacturers just stuck with nine pen peripherals rather 0:06:35.640 --> 0:06:39.040 than adopt the twenty five pen standard. Serial ports had 0:06:39.080 --> 0:06:42.200 a range of data transmission speeds from one hundred and 0:06:42.200 --> 0:06:46.400 fifteen to more than four hundred and fifty kilobits per second, 0:06:46.800 --> 0:06:51.279 so four hundred and fifty thousand bits per second was 0:06:51.360 --> 0:06:54.760 around the upper range of that. Now, some serial ports 0:06:54.800 --> 0:06:58.120 wouldn't allow for simultaneous operation, which meant that if the 0:06:58.160 --> 0:07:01.920 computer was sending out data through one serial port, it 0:07:01.960 --> 0:07:04.919 could not send out data to other serial ports at 0:07:04.960 --> 0:07:07.840 the same time. It's somewhat problematic if you're trying to 0:07:07.880 --> 0:07:11.440 do a whole lot of stuff connected to one machine. 0:07:11.480 --> 0:07:16.880 Parallel ports were often for stuff like CD burners, printers, scanners, 0:07:16.920 --> 0:07:19.200 and external hard drives where you wanted to have a 0:07:19.240 --> 0:07:21.880 faster data transfer because otherwise you're going to be sitting 0:07:21.880 --> 0:07:24.920 around for a really long time. So it's not that 0:07:24.960 --> 0:07:28.680 serial ports are necessarily bad for stuff. There are plenty 0:07:28.680 --> 0:07:31.320 of operations where you only need a little bit of 0:07:31.440 --> 0:07:35.320 data going between a device and a computer. It doesn't 0:07:35.480 --> 0:07:40.200 have to be super quote unquote fast because it's just 0:07:40.240 --> 0:07:43.040 not data hungry. But other things, like if you want 0:07:43.080 --> 0:07:45.720 a hard drive, you want something that's going to move 0:07:45.840 --> 0:07:49.440 data and larger amounts in that amount of time, because 0:07:50.200 --> 0:07:52.280 otherwise you're going to wait forever every time you try 0:07:52.280 --> 0:07:54.440 to save a large file to that hard drive or 0:07:54.480 --> 0:07:58.040 to retrieve a large file from that hard drive. Now, 0:07:58.080 --> 0:08:02.440 IBM developed parallel ports specifically to create an interface between 0:08:02.440 --> 0:08:05.560 a computer and a printer When IBM was first building 0:08:05.600 --> 0:08:09.360 personal computers, it partnered with a company called Centronics, and 0:08:09.480 --> 0:08:16.080 Centronics made computers. Centronics had a thirty six pin connector, 0:08:16.280 --> 0:08:19.200 meaning that the cable ended in a plug, and that 0:08:19.280 --> 0:08:22.720 plug had thirty six pins arranged in a row that 0:08:22.760 --> 0:08:26.160 would then plug into a port that had thirty six 0:08:26.240 --> 0:08:30.680 holes for those pins. IBM decided to couple this thirty 0:08:30.720 --> 0:08:34.280 six pin with a second line of pins twenty five 0:08:34.440 --> 0:08:37.600 in total. So together these two rows of pins were 0:08:37.679 --> 0:08:40.839 used as the standard for IBM computers, and when other 0:08:40.880 --> 0:08:44.240 companies began to create clones of the IBM PC, they 0:08:44.360 --> 0:08:48.240 also created those types of ports. I've got to do 0:08:48.280 --> 0:08:51.040 a full episode about IBM clones at some point. I 0:08:51.120 --> 0:08:53.479 talked about them briefly in a couple of other episodes, 0:08:53.800 --> 0:08:56.520 but really it's a fascinating thing to hear the story 0:08:56.559 --> 0:08:58.960 about how other companies were able to take advantage of 0:08:59.040 --> 0:09:04.160 IBM's design. Now it's called a parallel port because data 0:09:04.280 --> 0:09:08.359 would flow parallel to each other. Data traveled one byte 0:09:08.520 --> 0:09:11.760 at a time, not a bit, but a byte a 0:09:11.800 --> 0:09:15.000 collection of eight bits, which made parallel ports much faster 0:09:15.120 --> 0:09:17.920 than serial ports or mora acculately, it could send more 0:09:18.040 --> 0:09:20.839 data in the same amount of time. Parallel ports could 0:09:20.880 --> 0:09:25.360 transfer at about one hundred kilobytes per second. But Jonathan, 0:09:25.400 --> 0:09:27.240 I hear you say. You mentioned that serial ports have 0:09:27.280 --> 0:09:28.920 a range of one hundred and fifteen to four hundred 0:09:28.920 --> 0:09:31.560 and fifty kilobits per second. Yeah, I did say that. 0:09:31.600 --> 0:09:34.520 But parallel ports are sending bytes, not bits, and that 0:09:34.600 --> 0:09:36.839 bite is that collection of eight bits. So one hundred 0:09:36.920 --> 0:09:41.920 kilobytes is the same as approximately eight hundred kilobits. The 0:09:42.000 --> 0:09:45.079 parallel ports could send more data, though with some peripherals, 0:09:45.120 --> 0:09:48.320 this amount of data is really unnecessary, which is why 0:09:48.360 --> 0:09:50.960 serial ports didn't just disappear. They were still useful for 0:09:51.040 --> 0:09:55.320 certain applications, and they were cheap. So now let's talk 0:09:55.320 --> 0:09:57.720 about some of the pins in the parallel ports. We 0:09:57.760 --> 0:10:00.480 mentioned them in the serial ones. Well, if you were 0:10:00.520 --> 0:10:03.880 to look at them and number them across the row 0:10:04.520 --> 0:10:07.480 on both the twenty five pen and the sixty thirty 0:10:07.480 --> 0:10:10.520 six pin connectors, rather twenty five and thirty six pin connectors, 0:10:10.800 --> 0:10:16.480 Pens two through nine on those connectors carried those eight bits. 0:10:17.000 --> 0:10:19.760 Pen one carried a voltage between two point eight and 0:10:19.840 --> 0:10:22.880 five volts. The computer would drop the voltage to point 0:10:22.880 --> 0:10:25.600 five volts whenever it was sending data to a printer 0:10:25.720 --> 0:10:27.840 or other device, so that was kind of like an 0:10:27.880 --> 0:10:30.760 alert to a printer to be on the lookout for data. 0:10:31.320 --> 0:10:34.120 If it detected a voltage drop, it knew that information 0:10:34.240 --> 0:10:37.360 was incoming, so it's kind of a heads up. Pen 0:10:37.520 --> 0:10:41.560 ten was reserved for an acknowledge signal, this time sent 0:10:41.600 --> 0:10:45.000 from the printer to the computer. So this was essentially 0:10:45.400 --> 0:10:50.360 gotcha bro. So computer says heads up, printer says gotcha bro, 0:10:50.840 --> 0:10:53.360 and that lets the computer knows that the message had 0:10:53.400 --> 0:10:56.120 been received. Other pins were used to let the computer 0:10:56.200 --> 0:10:58.480 know if the printer was busy, or if it was 0:10:58.559 --> 0:11:01.040 out of paper or ink or something along those lines, 0:11:01.160 --> 0:11:06.480 or they were ground connectors as in electrical ground connectors. 0:11:07.480 --> 0:11:11.280 Future improvements in parallel processors allowed for bi directional communication, 0:11:11.440 --> 0:11:14.360 meaning that the printer and computer could talk to each other, 0:11:14.559 --> 0:11:18.720 not just one way communication. But the original standard only 0:11:18.760 --> 0:11:21.200 allowed data to flow one way at any given time, 0:11:21.720 --> 0:11:24.800 So ultimately you would get to parallel ports that could 0:11:24.800 --> 0:11:29.600 have simultaneous bidirectional communication, but that wasn't how it started. Now. 0:11:29.640 --> 0:11:33.480 As we created new peripherals for computers, we also created 0:11:33.600 --> 0:11:38.360 new ports. You'd use expansion cards for your computer, and 0:11:38.440 --> 0:11:41.400 those would plug into the main circuit board the motherboard 0:11:41.400 --> 0:11:45.360 on a computer to create the connection. So if you've 0:11:45.400 --> 0:11:48.040 never built a machine or ever had to customize one, 0:11:48.360 --> 0:11:50.840 this might sound a little weird, but here's what it meant. 0:11:50.880 --> 0:11:55.400 It meant you'd open up a computer case, you'd pop out. 0:11:55.520 --> 0:11:58.840 Typically there'd be a metal plate on the back side 0:11:59.000 --> 0:12:02.000 of a computer case that would cover up what would 0:12:02.000 --> 0:12:06.480 otherwise be just a kind of an oblong hole. You 0:12:06.520 --> 0:12:08.880 would end up taking the plate off of that so 0:12:08.920 --> 0:12:13.760 that the hole was open. You would insert a card 0:12:14.040 --> 0:12:18.240 into a slot on that main circuit board. It would 0:12:18.280 --> 0:12:21.760 seat the card properly, so you'd make sure that it 0:12:21.840 --> 0:12:24.319 was plugged in nice and snug, and you would make 0:12:24.360 --> 0:12:26.800 sure that you were using the card slot so that 0:12:27.000 --> 0:12:29.880 the back of the card is lined up with that 0:12:30.040 --> 0:12:33.680 new hole that you've uncovered on the back of your case. 0:12:34.640 --> 0:12:38.400 This would allow you to plug in devices externally from 0:12:38.440 --> 0:12:41.320 the computer. It would just plug in through that hole 0:12:41.400 --> 0:12:44.480 where the port would be. So the hole is the 0:12:44.520 --> 0:12:46.640 reason why the plate is there, is to keep the 0:12:46.679 --> 0:12:49.600 computer safe from stuff like dust. You know, you don't 0:12:49.640 --> 0:12:51.679 want to just have a bunch of open areas to 0:12:51.720 --> 0:12:53.880 your computer or else it can get dusty, which can 0:12:53.920 --> 0:12:57.760 then mess up the internal mechanisms. Not really even mechanisms. 0:12:57.840 --> 0:13:01.280 It can just make things overheat and break down and 0:13:01.320 --> 0:13:03.679 short out a computer if it's really really bad. That's 0:13:03.679 --> 0:13:05.520 why we have computer fans and stuff like that. It's 0:13:05.559 --> 0:13:07.320 not just to manage the heat, it's also to manage 0:13:07.360 --> 0:13:11.640 the dust. So you take that plate off, you reveal 0:13:11.720 --> 0:13:14.480 the spot, you've seated the card, you put it all 0:13:14.520 --> 0:13:17.840 back together, and then you would plug your new peripheral 0:13:17.920 --> 0:13:20.680 into your new port and you would turn on the 0:13:20.679 --> 0:13:22.400 computer and find out if it worked or not, and 0:13:22.480 --> 0:13:26.280 if it didn't work, you had to start troubleshooting. Typically, 0:13:26.280 --> 0:13:27.920 it would also mean you'd have to turn the computer 0:13:27.960 --> 0:13:31.079 off again, because the way a lot of these old 0:13:31.080 --> 0:13:33.800 systems work, they weren't plug and play. You couldn't hot 0:13:33.800 --> 0:13:37.400 plug a device into computers for a lot of these ports. 0:13:37.880 --> 0:13:40.400 That means that you had to actually turned the computer off, 0:13:41.240 --> 0:13:44.240 plug the device in, turn the computer on, and then 0:13:44.720 --> 0:13:48.280 it would start to pull information or send information to 0:13:48.400 --> 0:13:51.760 that device, kind of a primitive way of doing it. 0:13:51.960 --> 0:13:54.360 And on top of that, some of the devices had 0:13:54.400 --> 0:13:58.120 proprietary plugs and ports. For example, in nineteen eighty seven, 0:13:58.160 --> 0:14:01.920 IBM introduced the EPs slides two port for keyboards and 0:14:02.040 --> 0:14:07.680 mouses mices miss you know what I mean. The port 0:14:07.800 --> 0:14:12.400 is circular with six pins arranged in pairs around kind 0:14:12.440 --> 0:14:16.479 of a rectangular center, and it communicated through a serial protocol, 0:14:16.559 --> 0:14:18.840 but it had a totally different shape from your typical 0:14:18.920 --> 0:14:24.880 serial plugs and ports keyboards were similar. And then there's 0:14:24.920 --> 0:14:29.360 the idea that about plugging stuff while your computer is on. Yeah, 0:14:29.880 --> 0:14:33.360 not a thing at those times. A hot port would 0:14:33.400 --> 0:14:35.560 allow you to plug a device in whether a computer 0:14:35.680 --> 0:14:38.040 is on or off, and then the PC recognizes that 0:14:38.080 --> 0:14:40.680 there's a connection and it allows you to use whatever 0:14:40.680 --> 0:14:43.520 that device is. These old ports, for the most part, 0:14:43.640 --> 0:14:47.720 did not allow for that unless you had the computer 0:14:47.800 --> 0:14:50.120 turn on and go through its boot program and then 0:14:50.280 --> 0:14:54.120 detect all of these peripherals. It just didn't recognize that 0:14:54.240 --> 0:14:57.400 anything new was attached to it. So why don't we 0:14:57.560 --> 0:15:01.640 still depend upon these and other specialized ports. Well, some 0:15:01.680 --> 0:15:05.320 computers still have special serial or parallel ports, but most 0:15:05.400 --> 0:15:08.160 of them now have some type of USB port or 0:15:08.320 --> 0:15:11.680 HDMI port for some displays. And part of the problem 0:15:11.720 --> 0:15:14.760 is that over the years, the number of peripherals for 0:15:14.800 --> 0:15:18.880 computer systems grew substantially, but you can only fit so 0:15:19.000 --> 0:15:22.120 many ports on a computer. There's only so much physical 0:15:22.240 --> 0:15:25.920 space you can use, and each port required its own 0:15:26.120 --> 0:15:29.680 card plugged into a computer's motherboard, so there are only 0:15:29.680 --> 0:15:31.920 so many slots on a motherboard you could use. Up 0:15:32.200 --> 0:15:34.760 on top of that, you need to designate special numbers 0:15:34.800 --> 0:15:38.680 for each card plugging into the motherboard, and that included 0:15:38.720 --> 0:15:42.680 an interrupt request also known as an IRQ and an 0:15:42.720 --> 0:15:47.440 input output address or the IO address. Now, those numbers 0:15:47.440 --> 0:15:51.080 are hard coded onto cards, so it doesn't mean that 0:15:51.120 --> 0:15:53.240 you have to come up with a number, it's on 0:15:53.360 --> 0:15:55.840 the card itself. But that also meant that you could 0:15:55.880 --> 0:16:02.760 potentially encounter conflicts between different cards for different products. Let's 0:16:02.760 --> 0:16:06.120 say that you've got a video card from one company 0:16:06.560 --> 0:16:09.920 and a totally different peripheral card. Let's say it's for 0:16:10.160 --> 0:16:14.280 a specific type of scanner from another company, and just 0:16:14.440 --> 0:16:18.400 by coincidence, they have conflicts in either the IRAQ or 0:16:18.400 --> 0:16:22.640 the IO address. This could cause issues, and that would 0:16:22.680 --> 0:16:26.320 sometimes mean that peripherals would become incompatible with one another 0:16:26.360 --> 0:16:28.240 and that there'd be no way to run both off 0:16:28.280 --> 0:16:31.360 the same machine. So you might find that you can 0:16:31.400 --> 0:16:35.800 have either a display or a scanner attached to this computer, 0:16:36.000 --> 0:16:39.560 but not both not ideal, and then you had all 0:16:39.600 --> 0:16:42.800 the different kinds of plugs making it confusing to consumers. 0:16:42.880 --> 0:16:45.960 You can't just plug any peripheral into any port. That's 0:16:45.960 --> 0:16:49.160 why older computers frequently have color coded ports and helps 0:16:49.200 --> 0:16:51.400 the user know which one is for a keyboard versus 0:16:51.400 --> 0:16:54.640 a mouse, that kind of thing. So what would be 0:16:54.640 --> 0:16:57.280 the solution to this, Well, that would be the Universal 0:16:57.320 --> 0:17:00.000 Serial Bus And I'm going to go into more details 0:17:00.160 --> 0:17:03.080 about exactly how it pulled it off in just a second, 0:17:03.160 --> 0:17:07.040 but first let's take a quick break to thank our sponsor. 0:17:16.040 --> 0:17:19.800 So a much more attractive alternative to these serial and 0:17:19.840 --> 0:17:22.840 parallel ports is plug and play, which is that concept 0:17:22.840 --> 0:17:25.280 in which you can just plug a device in using 0:17:25.320 --> 0:17:30.360 a standardized connector on a standardized port and it just works. 0:17:30.840 --> 0:17:34.400 And USB can do that. It can also dramatically increase 0:17:34.440 --> 0:17:37.200 the number of peripherles you can attach to a single 0:17:37.760 --> 0:17:40.800 home device, whether it's a hub or a computer or whatever. 0:17:41.880 --> 0:17:45.760 The USB standard allows up to one hundred and twenty 0:17:45.920 --> 0:17:50.240 seven devices to connect to a single source. That would 0:17:50.280 --> 0:17:52.600 mean you need a few USB hubs to max it out, 0:17:53.960 --> 0:17:57.000 so you might have one thing plugged into a USB 0:17:57.119 --> 0:18:00.320 port that actually has five other USB ports in that 0:18:01.640 --> 0:18:04.359 Then you could expand that it's kind of like plugging 0:18:05.920 --> 0:18:10.399 like a bunch of power strips into each other in 0:18:10.520 --> 0:18:13.040 order to maximize the number of power cords that you 0:18:13.040 --> 0:18:16.640 can attach to one outlet, only slightly less dangerous. There's 0:18:16.640 --> 0:18:19.080 not really a huge risk for fire in the case 0:18:19.119 --> 0:18:21.720 of the one hundred and twenty seven devices attached to 0:18:21.760 --> 0:18:26.639 a single home computer. The important thing to remember really 0:18:26.720 --> 0:18:29.719 is that it opens up possibilities for far more connections 0:18:29.760 --> 0:18:32.760 than parallel or serial ports, which are one customer at 0:18:32.800 --> 0:18:36.720 a time kind of ports. And plugging a peripheral into 0:18:36.800 --> 0:18:39.399 a host computer is supposed to be easy with USB, 0:18:40.000 --> 0:18:42.360 assuming that you have it facing the right way. More 0:18:42.400 --> 0:18:45.240 on that in a second. The computer is in charge 0:18:45.240 --> 0:18:48.639 of communications, so it detects the type of device that 0:18:48.640 --> 0:18:51.760 gets plugged into any given USB board, and then the 0:18:51.800 --> 0:18:54.840 computer is supposed to load a compatible driver for whatever 0:18:54.880 --> 0:18:57.679 that peripheral is. And this is what allows a periphole 0:18:57.760 --> 0:19:00.399 device like a keyboard or a printer or a digital 0:19:00.440 --> 0:19:04.520 camera to communicate with the computer in a nice smooth way. 0:19:05.160 --> 0:19:09.400 Computers downstream data to devices which upstream data to computers 0:19:09.400 --> 0:19:13.320 and it's all very civilized, I assure you. There's another 0:19:13.359 --> 0:19:17.400 really important point. The USB protocol allows for powered connections. 0:19:17.440 --> 0:19:20.760 That means the ports and cables can carry electricity to 0:19:21.000 --> 0:19:26.240 power devices as well as a voltage to indicate data transfer, 0:19:26.320 --> 0:19:29.040 and that was really important. It allowed for options that 0:19:29.160 --> 0:19:33.000 simplified cable management. If a peripheral could transmit data and 0:19:33.040 --> 0:19:35.439 receive power through one cable, it could cut down on 0:19:35.480 --> 0:19:38.560 some clutter. So this is why you can find lots 0:19:38.640 --> 0:19:41.960 of little plug in toys and do dads that will 0:19:42.280 --> 0:19:45.320 attached via a USB cable. So it might be a 0:19:45.359 --> 0:19:50.239 little desk lamp or a little desktop missile launcher. I've 0:19:50.280 --> 0:19:52.440 seen those on Think Geek. I really need to get 0:19:52.480 --> 0:19:54.520 some of those. Hey, if anyone's over at think Geek 0:19:54.560 --> 0:19:57.920 and you got a few extra little USB missile launchers, 0:19:58.119 --> 0:20:00.960 send them to how stuff works. I think the office 0:20:01.000 --> 0:20:07.240 could really step up its intercompany warfare anyway. Now, we 0:20:07.359 --> 0:20:10.720 tend to use USB to refer to specific physical things 0:20:10.760 --> 0:20:13.320 like the ports or the cables, but you have to 0:20:13.359 --> 0:20:18.879 remember USB is an underlying technology protocol. The physical things 0:20:18.880 --> 0:20:23.239 we have are specific implementations of that technology, and they 0:20:23.240 --> 0:20:26.679 are dependent upon various versions of the USB Standard. But 0:20:26.760 --> 0:20:29.840 the standard is the real heart of USB. It's not 0:20:29.920 --> 0:20:32.440 a cable, it's not a device, it's not even a computer. 0:20:33.040 --> 0:20:38.160 It's the protocol that defines the behavior of USB. Now, 0:20:38.240 --> 0:20:41.880 right now, as I'm recording this episode, the most recent 0:20:42.119 --> 0:20:45.480 version of the USB standard is version three point one, 0:20:45.880 --> 0:20:48.000 and I'll talk more about what that means in just 0:20:48.040 --> 0:20:51.359 a moment. Before we can really look at where we 0:20:51.400 --> 0:20:53.560 stand right now, we should probably take a look at 0:20:53.560 --> 0:20:56.119 where it all got started. And you know me, you 0:20:56.200 --> 0:20:58.720 know I love my tech history. So how did the 0:20:58.840 --> 0:21:03.960 USB protocols into being? Wells Zeus on Mount Olympus once 0:21:04.000 --> 0:21:07.760 stubbed his toe and from that toe. I wish that 0:21:07.800 --> 0:21:09.560 were the case, because that would be a cool story. 0:21:09.600 --> 0:21:13.080 I love Greek mythology. But back in nineteen ninety four, 0:21:13.600 --> 0:21:17.600 an Intel developer named a jay Bot began working on 0:21:17.640 --> 0:21:21.920 a solution to this peripheral problem. And at the same time, 0:21:21.960 --> 0:21:26.040 there was a group called the USB Implementer's Forum Incorporated 0:21:26.160 --> 0:21:30.400 or USBIF that came into being, and that group included 0:21:30.440 --> 0:21:36.119 people from Intel, Compac, Apple, Hewitt, Packard, and Microsoft, among others. 0:21:36.760 --> 0:21:40.320 This confederation of companies was necessary in order to develop 0:21:40.320 --> 0:21:43.120 a standard protocol that would work across a vast array 0:21:43.119 --> 0:21:46.480 of computers and devices. So they wanted to make sure 0:21:46.600 --> 0:21:49.960 that if anyone incorporated this into their designs, it was 0:21:50.000 --> 0:21:52.760 incorporated across the board. Otherwise it would be limited in 0:21:52.800 --> 0:21:57.240 its usefulness. It certainly wouldn't become a universal serial bus. 0:21:57.800 --> 0:22:00.600 And they also really wanted to simplify ports. They wanted 0:22:00.640 --> 0:22:04.199 to reduce the half dozen standards with a single replacement, 0:22:04.320 --> 0:22:06.800 and ideally it wouldn't matter what you plugged into your 0:22:06.800 --> 0:22:09.960 computer or which port you used. It would just work. 0:22:10.000 --> 0:22:13.119 Whether you plugged it in the front the back didn't matter. 0:22:13.560 --> 0:22:16.680 The computer would automatically recognize it. That's what they wanted, 0:22:16.720 --> 0:22:18.960 so they had to create something to make it happen. 0:22:20.080 --> 0:22:23.560 In late nineteen ninety five, they did have something to 0:22:23.600 --> 0:22:26.119 show off. They had worked for a full year and 0:22:26.160 --> 0:22:30.040 they had developed the standard that was called USB one 0:22:30.160 --> 0:22:33.720 point zero. The protocol only gave a hint at what 0:22:33.920 --> 0:22:37.040 was to come. It could transmit data at twelve megabits 0:22:37.160 --> 0:22:41.200 per second, which was much faster than parallel or serial ports, 0:22:41.240 --> 0:22:45.520 though sluggish compared to today's technology. The revised USB one 0:22:45.560 --> 0:22:49.359 point one standard added in another capability of transferring data, 0:22:49.400 --> 0:22:53.359 but this time at one point five megabits per second, 0:22:54.040 --> 0:22:57.639 So why would you lower that quote unquote speed or 0:22:57.680 --> 0:23:01.280 the capacity if you prefer Well, the reason was that 0:23:01.320 --> 0:23:04.400 some devices just couldn't handle a bandwidth of twelve megabits 0:23:04.400 --> 0:23:07.119 per second. They didn't need it. They couldn't handle that much. 0:23:07.640 --> 0:23:11.560 So you needed to have a throttling mechanism in order 0:23:11.640 --> 0:23:15.240 to send data at the proper rate to those peripherals. 0:23:15.320 --> 0:23:17.960 And that was the solution of USB one point one, 0:23:19.520 --> 0:23:22.000 and one point one got the most US. In those 0:23:22.000 --> 0:23:25.080 early days, not a whole lot of devices used USB 0:23:25.280 --> 0:23:27.960 one point zero. Almost everyone was using one point one 0:23:28.040 --> 0:23:30.640 from as soon as it was available. It just made 0:23:30.720 --> 0:23:34.919 more sense. The first computer to eschew all other ports 0:23:34.960 --> 0:23:38.000 in favor of the new USB standard was the iMac 0:23:38.240 --> 0:23:42.200 G three in nineteen ninety eight. So Apple led the way. 0:23:43.600 --> 0:23:47.480 It probably comes as a surprise to absolutely no one 0:23:47.520 --> 0:23:49.919 out there in the audience, because Apple is known for 0:23:50.080 --> 0:23:53.560 dumping legacy systems in favor of new technology, at least 0:23:53.600 --> 0:23:56.959 with their computers, if not their mobile devices. Sometimes they 0:23:57.000 --> 0:23:59.760 hold back with mobile devices, but they charge ahead with 0:23:59.800 --> 0:24:03.679 their computers. So with USB devices, it wasn't such a 0:24:03.680 --> 0:24:07.320 big deal. Since we're talking about a universal standard. In 0:24:07.359 --> 0:24:11.280 other cases, Apple has sometimes gone a more proprietary approach, 0:24:11.320 --> 0:24:14.280