WEBVTT - How USB Ports Work 0:00:04.200 --> 0:00:07.280 Get in touch with technology with tech Stuff from house 0:00:07.280 --> 0:00:14.440 stuff works dot com. Hey there, and welcome to tech stuff. 0:00:14.520 --> 0:00:18.240 I'm your host, Jonathan Strickland, senior writer for a house 0:00:18.239 --> 0:00:21.239 stuff works dot com, and today I wanted to take 0:00:21.239 --> 0:00:25.520 a look at a technology protocol that's become ubiquitous, one 0:00:25.680 --> 0:00:30.520 might even say universal. I'm talking about the Universal Serial Bus, 0:00:30.560 --> 0:00:35.600 better known as USB. Now you'll find these ports on computers, smartphones, 0:00:35.800 --> 0:00:40.000 digital cameras, scanners, printers, and tons of other electronic devices. 0:00:40.000 --> 0:00:43.080 So what are they, who invented them? And how do 0:00:43.159 --> 0:00:48.080 they work? You know, your standard tech stuff type episode. Well, 0:00:48.760 --> 0:00:52.040 you could just go and read the specification for USB 0:00:52.159 --> 0:00:54.240 if you really wanted to, and that would give you 0:00:54.320 --> 0:00:58.440 all the information you need and more. For example, the 0:00:58.720 --> 0:01:01.960 specification for USB two point oh is a mirror six 0:01:02.080 --> 0:01:07.399 hundred fifty pages long. It seems a bit excessive to me, 0:01:07.480 --> 0:01:11.800 So let's break down the topic tech stuff style. So first, 0:01:11.840 --> 0:01:15.440 let's talk about what a bus is. In computer terms, 0:01:15.880 --> 0:01:19.160 a bus is essentially a conduit for data. Think of 0:01:19.200 --> 0:01:22.600 it like a hallway that data can pass through. It's 0:01:22.600 --> 0:01:26.520 a communication pathway that lets different components within a computer 0:01:26.840 --> 0:01:30.760 or two different devices send data back and forth between 0:01:30.800 --> 0:01:35.559 each other. That means some buses are internal and facilitate 0:01:35.600 --> 0:01:40.240 communication within a single device. Other buses are external and 0:01:40.280 --> 0:01:44.720 allow for the communication of different components like a smartphone 0:01:44.800 --> 0:01:48.840 to a computer for example. So inside a computer, you 0:01:48.880 --> 0:01:52.880 would have a bus connecting components like the microprocessor and 0:01:53.080 --> 0:01:56.640 a memory storage device like a hard drive. So the 0:01:56.640 --> 0:02:00.400 computers operating memory and CPU tend to be very closely 0:02:00.520 --> 0:02:03.600 tied together, as in its operating memory like the random 0:02:03.600 --> 0:02:07.760 access memory. That and the CPU are usually real tight, 0:02:08.200 --> 0:02:10.600 but they still have a bus. It's usually called the 0:02:10.639 --> 0:02:15.040 system bus that connects the two. And just as microprocessors 0:02:15.120 --> 0:02:18.720 and memory have improved over time, so if buses, they've 0:02:18.760 --> 0:02:21.880 improved to allow more data to pass through at a 0:02:21.919 --> 0:02:25.520 single time. Now, keep in mind information is traveling at 0:02:25.560 --> 0:02:28.239 pretty much the same speed, you know, more or less 0:02:28.280 --> 0:02:31.600 the speed of light. It's not quite the same, but 0:02:32.080 --> 0:02:35.520 for the purposes of our argument, it works just fine. 0:02:36.520 --> 0:02:39.360 So really the question is how much data can you 0:02:39.440 --> 0:02:43.079 move through the bus simultaneously? Or if we wanted to 0:02:43.200 --> 0:02:47.359 use a metaphor, imagine that you have an eye dropper 0:02:48.200 --> 0:02:51.720 and your friend has a bucket, and you're each taking 0:02:51.800 --> 0:02:55.880 water from one puddle and walking across a field at 0:02:55.880 --> 0:03:00.400 the same speed and depositing that water into a little 0:03:00.480 --> 0:03:02.880 dip and the other end of the field that's going 0:03:02.919 --> 0:03:06.080 to become the new puddle. So you're just relocating water 0:03:06.160 --> 0:03:08.799 from one puddle to the other. Now you're walking at 0:03:08.800 --> 0:03:11.880 the same speed, so you're not It's not that your 0:03:11.960 --> 0:03:14.359 friend is going faster than you are, but they can 0:03:14.400 --> 0:03:18.640 carry more water per trip, so they're delivering more water 0:03:18.800 --> 0:03:21.920 every time they make this trip, and even though you're 0:03:21.960 --> 0:03:24.119 both going the same speed. This is why I get 0:03:24.120 --> 0:03:28.440 a little antsie about data speeds, because it's not really 0:03:28.440 --> 0:03:31.160 so much about speed. It's more about the amount of 0:03:31.280 --> 0:03:34.560 data you can carry at a time. That's kind of 0:03:34.560 --> 0:03:37.120 what I'm getting at. So if you hear like this 0:03:37.160 --> 0:03:41.960 computer sends data faster than that computer, the information is 0:03:41.960 --> 0:03:44.360 still traveling it more or less the same speed, depending 0:03:44.400 --> 0:03:48.920 upon what you know medium they're using, But it all 0:03:49.400 --> 0:03:52.680 is down to how much information can pass through at 0:03:52.720 --> 0:03:56.560 any given time. Now, there are also busses that allow 0:03:56.680 --> 0:04:01.120 data transfers with sources that are external to a computer. Again, 0:04:01.160 --> 0:04:04.040 the smartphone is a great example, where a digital cameras, 0:04:04.160 --> 0:04:08.520 anything like that. The buses facilitate the data transfer which 0:04:08.600 --> 0:04:11.640 typically happens over a cable, And there are plenty ways 0:04:11.680 --> 0:04:15.559 to transmit data wirelessly, but we're just going to concentrate 0:04:15.600 --> 0:04:19.560 on cables and tethered peripherals today because that's what USB 0:04:20.120 --> 0:04:22.720 works with, right, That's the protocol, is that you're using 0:04:22.760 --> 0:04:27.200 physical connections. In other episodes, I'll talk about stuff like 0:04:27.800 --> 0:04:33.400 WiFi or Bluetooth or other methods of transferring data around. Now. 0:04:33.440 --> 0:04:36.480 Before USB ports became a standard way to connect various 0:04:36.480 --> 0:04:39.960 components to a computer, we had to rely on other 0:04:40.120 --> 0:04:45.360 types of ports, like parallel and serial ports. Cereal ports 0:04:45.400 --> 0:04:50.200 are se r I a L ports, not not cereal 0:04:50.360 --> 0:04:54.960 like Captain crunch. They're basic computer connections. They send bytes 0:04:55.040 --> 0:04:59.119 of data one bit at a time. So, in case 0:04:59.240 --> 0:05:04.320 you don't remember basic computer lingo, a bite is eight bits, 0:05:04.720 --> 0:05:08.400 and a bit is a single unit of information in 0:05:08.480 --> 0:05:11.800 computer speech, it's either a zero or a one, which 0:05:11.839 --> 0:05:14.960 is kind of like an off on switch, So a 0:05:15.040 --> 0:05:20.960 bite is eight of these collected together. Serial ports send 0:05:21.360 --> 0:05:25.440 information one bit at a time, one zero or one one, 0:05:26.560 --> 0:05:29.799 and then does a whole sequence of those Serial parts 0:05:29.800 --> 0:05:34.039 had either nine or twenty five pens. The nine pin 0:05:34.080 --> 0:05:37.479 connector was a standard for modems. We're talking about the 0:05:37.520 --> 0:05:40.039 old dial up modems that would connect to your phone 0:05:40.080 --> 0:05:44.200 line and allow your computer to communicate with the outside world. 0:05:44.640 --> 0:05:47.479 If you don't know what a dial up modem is, uh, 0:05:47.720 --> 0:05:51.440 you know, ask your parents. Each pen was designed to 0:05:51.480 --> 0:05:54.680 allow for communication between the computer and the modem in 0:05:54.760 --> 0:05:57.880 some way. The pin connector was meant to become a 0:05:57.920 --> 0:06:00.520 new standard, but with so much larger than the nine 0:06:00.520 --> 0:06:03.400 pin connectors that it was a bit hamstrung from the start. 0:06:03.600 --> 0:06:06.240 Not everyone adopted it. In fact, a lot of manufacturers 0:06:06.279 --> 0:06:10.920 just stuck with nine pen peripherals rather than adopt the standard. 0:06:11.240 --> 0:06:14.479 Serial ports had a range of data transmission speeds from 0:06:14.800 --> 0:06:18.920 one fifteen to more than four hundred fifty kill abits 0:06:18.920 --> 0:06:23.919 per second, so four hundred fifty thousand bits per second 0:06:24.360 --> 0:06:27.640 was around the upper range of that. Now, some serial 0:06:27.680 --> 0:06:31.240 ports wouldn't allow for simultaneous operation, which meant that if 0:06:31.240 --> 0:06:34.760 the computer was sending out data through one serial port, 0:06:35.000 --> 0:06:37.960 it could not send out data to other serial parts 0:06:38.000 --> 0:06:40.960 at the same time, and somewhat problematic if you're trying 0:06:40.960 --> 0:06:43.279 to do a whole lot of stuff connected to one machine. 0:06:44.640 --> 0:06:49.480 Parallel ports were often for stuff like CD burners, printers, 0:06:49.480 --> 0:06:52.240 scanners and external hard drives where you wanted to have 0:06:52.320 --> 0:06:55.040 a faster data transfer because otherwise you're gonna be sitting 0:06:55.080 --> 0:06:58.080 around for a really long time. So it's not that 0:06:58.160 --> 0:07:01.840 sereal parts are necessarily bad for stuff. There are plenty 0:07:01.880 --> 0:07:04.520 of operations where you only need a little bit of 0:07:04.600 --> 0:07:08.560 data going between a device and a computer. It doesn't 0:07:08.640 --> 0:07:13.360 have to be super quote unquote fast because it's just 0:07:13.400 --> 0:07:16.240 not data hungry. But other things, like if you want 0:07:16.280 --> 0:07:18.920 a hard drive, you want something that's going to move 0:07:19.000 --> 0:07:22.680 data and larger amounts in that amount of time, because 0:07:23.400 --> 0:07:25.560 otherwise you're gonna wait forever every time you try to 0:07:25.600 --> 0:07:27.760 save a large file to that hard drive or to 0:07:27.840 --> 0:07:31.680 retrieve a large file from that hard drive. Now, IBM 0:07:31.720 --> 0:07:35.720 developed parallel ports specifically to create an interface between a 0:07:35.720 --> 0:07:39.640 computer and a printer. When IBM was first building personal computers, 0:07:39.680 --> 0:07:44.920 it partnered with a company called Centronics, and Centronics made computers. 0:07:46.200 --> 0:07:50.120 Centronics had a thirty six pin connector, meaning that the 0:07:50.200 --> 0:07:53.280 cable ended in a plug and that plug had thirty 0:07:53.320 --> 0:07:57.120 six pins arranged in a row that would then plug 0:07:57.280 --> 0:08:00.920 into a port that had thirty six holes for those pins. 0:08:01.480 --> 0:08:05.000 IBM decided to couple this thirty six pin with a 0:08:05.120 --> 0:08:09.360 second line of pins twenty five in total. So together 0:08:09.440 --> 0:08:11.880 these two rows of pins were used as the standard 0:08:11.880 --> 0:08:15.160 for IBM computers, and when other companies began to create 0:08:15.200 --> 0:08:19.400 clones of the IBM PC, they also created those types 0:08:19.480 --> 0:08:22.480 of ports. I've got to do a full episode about 0:08:22.480 --> 0:08:25.000 IBM clones at some point, and I talked about them 0:08:25.040 --> 0:08:27.600 briefly in a couple of other episodes. But really it's 0:08:27.600 --> 0:08:30.440 a fascinating thing to hear the story about how other 0:08:30.480 --> 0:08:34.839 companies were able to take advantage of IBM's design. Now 0:08:34.840 --> 0:08:38.559 it's called a parallel port because data would flow parallel 0:08:38.840 --> 0:08:42.319 to each other. Data traveled one byte at a time, 0:08:43.200 --> 0:08:46.079 not a bit, but a bite, a collection of eight bits, 0:08:46.400 --> 0:08:49.360 which made parallel ports much faster than serial ports, or 0:08:49.559 --> 0:08:52.000 more accurately, it could send more data in the same 0:08:52.040 --> 0:08:55.280 amount of time. Parallel ports could transfer at about one 0:08:55.880 --> 0:08:59.320 kilobytes per second. But Jonathan, I hear you say. You 0:08:59.360 --> 0:09:00.880 mentioned that Series A boards have a range of a 0:09:00.920 --> 0:09:04.400 hundred fifty kill a bits per second. Yeah, I did 0:09:04.400 --> 0:09:07.400 say that, But parallel parts are sending bytes, not bits, 0:09:07.400 --> 0:09:09.480 and that bite is that collection of eight bits, So 0:09:09.559 --> 0:09:13.040 one kill of bytes is the same as approximately eight 0:09:13.120 --> 0:09:16.960 hundred kill of bits. The parallel ports could send more data, 0:09:17.120 --> 0:09:20.960 though with some peripherals this amount of data is really unnecessary, 0:09:21.040 --> 0:09:23.360 which is why serial ports didn't just disappear. They were 0:09:23.360 --> 0:09:27.760 still useful for certain applications, and they were cheap. So 0:09:27.840 --> 0:09:29.960 now let's talk about some of the pins in the 0:09:30.000 --> 0:09:32.480 parallel parts. We mentioned them in the serial ones. Well, 0:09:33.320 --> 0:09:35.760 if you were to look at them and number them 0:09:35.880 --> 0:09:39.760 across the row on both the pen and the sixty 0:09:40.400 --> 0:09:44.320 thirty six pin connectors rather thirty six pin connectors, pins 0:09:44.360 --> 0:09:49.760 two through nine on those connectors carried those eight bits. 0:09:50.160 --> 0:09:52.960 PEN one carried a voltage between two point eight and 0:09:53.000 --> 0:09:56.040 five volts. The computer would drop the voltage to point 0:09:56.080 --> 0:09:58.800 five volts whenever it was sending data to a printer 0:09:58.920 --> 0:10:01.040 or other device, so that was kind of like an 0:10:01.080 --> 0:10:03.920 alert to a printer to be on the lookout for data. 0:10:04.520 --> 0:10:07.360 If it detected a voltage drop, it knew that information 0:10:07.440 --> 0:10:10.560 was incoming, so it's kind of a heads up. PEN 0:10:10.679 --> 0:10:14.720 ten was reserved for an acknowledge signal, this time sent 0:10:14.800 --> 0:10:18.160 from the printer to the computer, So this was essentially 0:10:18.559 --> 0:10:22.920 got you, bro So computer says heads up, printer says, 0:10:23.000 --> 0:10:25.920 got you bro and that lets the computer knows that 0:10:26.000 --> 0:10:28.719 the message had been received. Other pens were used to 0:10:28.800 --> 0:10:31.200 let the computer know if the printer was busy, or 0:10:31.240 --> 0:10:33.440 if it was out of paper or ink or something 0:10:33.480 --> 0:10:37.840 along those lines, or they were ground connectors as an 0:10:37.840 --> 0:10:42.959 electrical ground connectors. Future improvements and parallel processors allowed for 0:10:43.080 --> 0:10:47.000 bidirectional communication, meaning that the printer and computer could talk 0:10:47.040 --> 0:10:50.760 to each other, not just one way communication. But the 0:10:50.800 --> 0:10:53.440 original standard only allowed data to flow one way at 0:10:53.480 --> 0:10:57.280 any given time. So ultimately you would get to parallel 0:10:57.320 --> 0:11:01.160 ports that could have simultaneous bidirectional communication. But that wasn't 0:11:01.200 --> 0:11:05.280 how it started. Now, as we created new peripherals for computers, 0:11:05.600 --> 0:11:10.480 we also created new ports. You'd use expansion cards for 0:11:10.520 --> 0:11:13.520 your computer, and those would plug into the main circuit 0:11:13.559 --> 0:11:16.920 board the motherboard on a computer to create the connection. 0:11:17.520 --> 0:11:20.160 So if you've never built a machine or ever had 0:11:20.200 --> 0:11:23.160 to customize one, this might sound a little weird, but 0:11:23.280 --> 0:11:25.600 here's what it meant. It meant you'd open up a 0:11:25.640 --> 0:11:29.880 computer case, you'd pop out. Typically there'd be a metal 0:11:29.960 --> 0:11:33.400 plate on the back side of a computer case that 0:11:33.440 --> 0:11:36.640 would cover up what would otherwise be just a kind 0:11:36.640 --> 0:11:40.720 of an oblong hole. Uh, you would end up taking 0:11:40.720 --> 0:11:43.960 the plate off of that so that the hole was open, 0:11:44.640 --> 0:11:48.880 you would insert a card into a slot on the 0:11:49.160 --> 0:11:53.160 that main circuit board. UH. It would seat the card properly, 0:11:53.679 --> 0:11:55.840 so you'd make sure that it was plugged in nice 0:11:55.880 --> 0:11:58.120 and snug, and you would make sure that you were 0:11:58.200 --> 0:12:01.160 using the card slot so that the back of the 0:12:01.240 --> 0:12:04.800 card is lined up with that new hole that you've 0:12:04.880 --> 0:12:08.200 uncovered on the back of your case. UH. This would 0:12:08.200 --> 0:12:12.160 allow you to plug in devices externally from the computer. 0:12:12.720 --> 0:12:15.079 It would just plug in through that hole where the 0:12:15.400 --> 0:12:18.200 port would be. So the whole is the reason why 0:12:18.240 --> 0:12:20.600 the plate is there is to keep the computers safe 0:12:20.640 --> 0:12:23.040 from stuff like dust. You know, you don't want to 0:12:23.080 --> 0:12:25.520 just have a bunch of open areas to your computer 0:12:25.640 --> 0:12:27.920 or else it can get dusty, which can then mess 0:12:28.000 --> 0:12:31.319 up the internal mechanisms. Not really even mechanisms. It can 0:12:31.360 --> 0:12:34.959 just make things overheat and break down and short out 0:12:34.960 --> 0:12:37.120 a computer if it's really really bad. That's why we 0:12:37.160 --> 0:12:39.000 have computer fans and stuff like that. It's not just 0:12:39.040 --> 0:12:40.959 to manage the heat, it's also to manage the dust. 0:12:41.800 --> 0:12:45.400 So you take that plate off, you reveal the spot 0:12:45.720 --> 0:12:48.240 you've seated the card, you put it all back together, 0:12:48.840 --> 0:12:51.559 and then you would plug your new puripheral into your 0:12:51.600 --> 0:12:54.360 new port and you would turn on the computer and 0:12:54.400 --> 0:12:55.880 find out if it worked or not, and if it 0:12:55.960 --> 0:12:59.720 didn't work, you had to start troubleshooting. Typically it would 0:12:59.760 --> 0:13:01.600 also and you'd have to turn the computer off again 0:13:01.679 --> 0:13:04.880 because the way a lot of these old systems work, 0:13:04.920 --> 0:13:07.560 they weren't plug in play. You couldn't hot plug a 0:13:07.679 --> 0:13:11.160 device into computers for a lot of these ports. That 0:13:11.280 --> 0:13:14.720 means that you had actually turned the computer off, plug 0:13:14.800 --> 0:13:17.960 the device in, turned the computer on, and then it 0:13:18.000 --> 0:13:22.160 would start to pull information or send information to that device, 0:13:23.480 --> 0:13:25.360 kind of a primitive way of doing it. And on 0:13:25.440 --> 0:13:28.840 top of that, some of the devices had proprietary plugs 0:13:28.840 --> 0:13:33.400 and ports. For example, in IBM introduced the ps slash 0:13:33.520 --> 0:13:39.400 two port for keyboards and mouses, micesces you know what 0:13:39.480 --> 0:13:43.959 I mean. The port is circular with six pens arranged 0:13:44.000 --> 0:13:47.680 in pairs around kind of a rectangular center, and it 0:13:47.720 --> 0:13:50.520 communicated through a serial protocol, but it had a totally 0:13:50.520 --> 0:13:55.959 different shape from your typical cereal plugs and ports keyboards 0:13:55.960 --> 0:14:00.720 were similar. And then there's the idea that about plugging 0:14:00.720 --> 0:14:03.560 stuff while your computer is on. Yeah, not a thing 0:14:03.600 --> 0:14:07.000 at those times. A hot port would allow you to 0:14:07.040 --> 0:14:09.600 plug a device in whether a computer is on or off, 0:14:09.640 --> 0:14:12.320 and then the PC recognizes that there's a connection and 0:14:12.400 --> 0:14:15.959 it allows you to use whatever that devices. These old ports, 0:14:16.000 --> 0:14:19.440 for the most part, did not allow for that unless 0:14:19.480 --> 0:14:22.080 you had the computer turn on and go through its 0:14:22.120 --> 0:14:25.600 boot program and then detect all of these peripherals. It 0:14:25.720 --> 0:14:29.040 just didn't recognize that anything new was attached to it. 0:14:29.200 --> 0:14:32.800 So why don't we still depend upon these and other 0:14:33.040 --> 0:14:36.840 specialized ports. Well, some computers still have special serial or 0:14:36.840 --> 0:14:40.240 parallel ports, but most of them now have some type 0:14:40.280 --> 0:14:44.200 of USB port or HDMI port for some displays. And 0:14:44.240 --> 0:14:46.840 part of the problem is that over the years, the 0:14:46.920 --> 0:14:51.120 number of peripherals for computer systems grew substantially, but you 0:14:51.160 --> 0:14:54.320 can only fit so many ports on a computer. There's 0:14:54.320 --> 0:14:58.000 only so much physical space you can use, and each 0:14:58.040 --> 0:15:01.520 port required its own card blood into a computer's motherboard, 0:15:02.200 --> 0:15:04.320 so there are only so many slots on a motherboard 0:15:04.320 --> 0:15:06.360 you could use. Up on top of that, you need 0:15:06.400 --> 0:15:10.680 to designate special numbers for each card plugging into the motherboard, 0:15:11.120 --> 0:15:14.200 and that included an interrupt request also known as an 0:15:14.200 --> 0:15:17.760 I r Q, and an input output address or the 0:15:17.880 --> 0:15:22.960 IO address. Now, those numbers are hard coded onto cards, 0:15:23.600 --> 0:15:25.000 so it doesn't mean that you have to come up 0:15:25.040 --> 0:15:27.960 with a number, it's on the card itself. But that 0:15:28.040 --> 0:15:33.760 also meant that you could potentially encounter conflicts between different 0:15:33.920 --> 0:15:37.280 cards for different products. Let's say that you've got, you know, 0:15:37.360 --> 0:15:41.120 a video card from one company and a totally different 0:15:41.240 --> 0:15:44.400 peripheral card. Let's say it's for a specific type of 0:15:44.400 --> 0:15:48.920 scanner from another company, and just by coincidence, they have 0:15:49.240 --> 0:15:52.880 conflicts in either the ir Q or the I O address. 0:15:52.920 --> 0:15:56.680 This could cause issues, and that would sometimes mean that 0:15:56.680 --> 0:16:00.200 peripherals would become incompatible with one another, and that no 0:16:00.280 --> 0:16:03.280 way to run both off the same machine. So you 0:16:03.400 --> 0:16:07.400 might find that you can have either a display or 0:16:07.440 --> 0:16:11.480 a skinner attached to this computer, but not both. Not ideal, 0:16:11.960 --> 0:16:14.320 And then you had all the different kinds of plugs 0:16:14.360 --> 0:16:17.160 making it confusing to consumers. You can't just plug any 0:16:17.160 --> 0:16:20.680 peripheral into any port. That's why older computers frequently have 0:16:20.800 --> 0:16:23.360 color coded ports and helps the user know which one 0:16:23.400 --> 0:16:25.720 is for a keyboard versus a mouse, that kind of thing. 0:16:27.160 --> 0:16:29.480 So what would be the solution to this, Well, that 0:16:29.520 --> 0:16:32.200 would be the universal Cereal bus. And I'm going to 0:16:32.320 --> 0:16:34.680 go into more detail about exactly how it pulled it 0:16:34.720 --> 0:16:38.080 off in just a second, but first let's take a 0:16:38.160 --> 0:16:49.560 quick break to thank our sponsor. So a much more 0:16:49.600 --> 0:16:53.800 attractive alternative to these serial and parallel ports is plug 0:16:53.840 --> 0:16:56.040 and play, which is that concept in which you can 0:16:56.040 --> 0:16:59.560 just plug a device in using a standardized connector on 0:16:59.640 --> 0:17:04.479 a aderdized port and it just works. And USB can 0:17:04.520 --> 0:17:07.760 do that. It can also dramatically increase the number of 0:17:07.760 --> 0:17:11.720 peripherals you can attach to a single home device, whether 0:17:11.760 --> 0:17:15.080 it's a hub or a computer or whatever. The USB 0:17:15.240 --> 0:17:20.480 standard allows up to one twenty seven devices to connect 0:17:20.680 --> 0:17:23.480 to a single source. That would mean you need a 0:17:23.480 --> 0:17:27.240 few USB hubs to max it out, so you might 0:17:27.280 --> 0:17:30.600 have one thing plugged into a USB port that actually 0:17:30.640 --> 0:17:34.800 has five other USB ports in that then you could 0:17:34.840 --> 0:17:38.159 expand that. It's kind of like plugging, um, you know, 0:17:38.600 --> 0:17:43.119 like a bunch of power strips into each other in 0:17:43.200 --> 0:17:45.760 order to maximize the number of power chords that you 0:17:45.760 --> 0:17:49.359 can attach to one outlet, only slightly less dangerous. There's 0:17:49.359 --> 0:17:51.800 not really a huge risk for fire in the case 0:17:51.840 --> 0:17:54.879 of the hundred twenty seven devices attached to a single 0:17:55.680 --> 0:17:59.600 home computer. The important thing to remember really is that 0:17:59.640 --> 0:18:03.120 it opens up possibilities for far more connections than parallel 0:18:03.240 --> 0:18:05.920 or serial ports, which are one customer at a time 0:18:06.000 --> 0:18:09.600 kind of ports. And plugging a peripher role into a 0:18:09.640 --> 0:18:13.160 host computer is supposed to be easy with USB, assuming 0:18:13.160 --> 0:18:15.320 that you haven't facing the right way. More on that 0:18:15.359 --> 0:18:18.879 in a second. The computer is in charge of communications, 0:18:19.480 --> 0:18:21.959 so it detects the type of device that gets plugged 0:18:21.960 --> 0:18:25.040 into any given USB board, and then the computer is 0:18:25.040 --> 0:18:28.040 supposed to load a compatible driver for whatever that periph 0:18:28.119 --> 0:18:30.800 role is. And this is what allows a peripheral device 0:18:30.880 --> 0:18:33.480 like a keyboard or a printer or a digital camera 0:18:33.600 --> 0:18:36.480 to communicate with the computer in a in a nice 0:18:36.520 --> 0:18:41.399 smooth way. Computers downstream data to devices which upstream data 0:18:41.440 --> 0:18:44.280 to computers, and it's all very civilized, I assure you. 0:18:45.280 --> 0:18:48.320 I mean, there's another really important point. The USB protocol 0:18:48.359 --> 0:18:51.720 allows for powered connections. That means the ports and cables 0:18:51.760 --> 0:18:55.760 can carry electricity to power devices as well as a 0:18:56.000 --> 0:19:00.000 voltage to indicate data transfer. And that was really importan 0:19:00.080 --> 0:19:04.000 and it allowed for options that simplified cable management. If 0:19:04.000 --> 0:19:07.200 a peripheral could transmit data and receive power through one cable, 0:19:07.240 --> 0:19:09.919 it could cut down on some clutter. So This is 0:19:09.960 --> 0:19:12.960 why you can find lots of little plug in toys 0:19:13.000 --> 0:19:16.800 and do dads that will attached via a USB cable. 0:19:16.920 --> 0:19:19.800 So it might be a little desk lamp or a 0:19:19.840 --> 0:19:23.560 little a little desktop missile launcher. I've seen those on 0:19:23.680 --> 0:19:25.880 Think Geek. I really need to get some of those. Hey, 0:19:25.920 --> 0:19:27.760 if anyone's over at Think Geek and you've got a 0:19:27.840 --> 0:19:31.399 few extra little USB missile launchers, send them to how 0:19:31.440 --> 0:19:34.840 stuff works? Uh. I think the office could really step 0:19:34.920 --> 0:19:40.439 up its inter company warfare anyway. Now, we tend to 0:19:40.520 --> 0:19:43.720 use USB to refer to specific physical things like the 0:19:43.800 --> 0:19:47.520 ports or the cables, but you have to remember USB 0:19:47.880 --> 0:19:51.920 is an underlying technology protocol. The physical things we have 0:19:52.000 --> 0:19:56.520 are specific implementations of that technology, and they are dependent 0:19:56.560 --> 0:20:00.000 upon various versions of the USB standard. But the standard, 0:20:00.000 --> 0:20:03.080 it is the real heart of USB. It's not a cable, 0:20:03.200 --> 0:20:06.000 it's not a device, it's not even a computer. It's 0:20:06.040 --> 0:20:11.400 the protocol that defines the behavior of USB. Now, right now, 0:20:11.440 --> 0:20:15.560 as I'm recording this episode, the most recent version of 0:20:15.720 --> 0:20:18.920 the USB standard is version three point one, and I'll 0:20:18.920 --> 0:20:21.240 talk more about what that means in just a moment 0:20:22.440 --> 0:20:24.560 before we can really look at where we stand right 0:20:24.600 --> 0:20:26.760 now we should probably take a look at where it 0:20:26.880 --> 0:20:29.159 all got started. And you know me, you know I 0:20:29.240 --> 0:20:32.480 love my tech history. So how did the USB protocol 0:20:32.560 --> 0:20:37.120 spring into being? Wells use on Mount Olympus once stubbed 0:20:37.160 --> 0:20:40.680 his toe and from that toe. I wish that were 0:20:40.720 --> 0:20:42.399 the case, because that would be a cool story. I 0:20:42.440 --> 0:20:48.359 love Greek mythology. But back in an Intel developer named A. J. 0:20:48.560 --> 0:20:52.440 Bott began working on a solution to this peripheral problem. 0:20:53.240 --> 0:20:55.639 And at the same time, there was a group called 0:20:55.680 --> 0:21:00.159 the USB implement Ers Forum Incorporated or USB dash i 0:21:00.400 --> 0:21:03.440 F that came into being, and that group included people 0:21:03.520 --> 0:21:09.440 from Intel, Compact, Apple, Hewitt, Packard, and Microsoft, among others. 0:21:09.440 --> 0:21:13.000 This confederation of companies was necessary in order to develop 0:21:13.040 --> 0:21:15.800 a standard protocol that would work across a vast array 0:21:15.840 --> 0:21:19.200 of computers and devices. So they wanted to make sure 0:21:19.320 --> 0:21:22.639 that if anyone incorporated this into their designs, it was 0:21:22.680 --> 0:21:25.480 incorporated across the board, otherwise it would be limited in 0:21:25.480 --> 0:21:29.760 its usefulness. It certainly wouldn't become a universal serial bus. 0:21:30.520 --> 0:21:33.320 And they also really wanted to simplify ports. They wanted 0:21:33.320 --> 0:21:36.920 to reduce the half dozen standards with a single replacement 0:21:37.040 --> 0:21:39.479 and ideally it wouldn't matter what you plugged into your 0:21:39.520 --> 0:21:42.640 computer or which port you used. It would just work. 0:21:42.680 --> 0:21:45.760 Whether you plugged it in the front the back didn't matter. 0:21:46.240 --> 0:21:49.360 The computer would automatically recognize it. That's what they wanted, 0:21:49.400 --> 0:21:51.679 so they had to create something to make it happen. 0:21:52.760 --> 0:21:56.919 In late they did have something to show off. They 0:21:56.920 --> 0:21:59.760 had worked for a full year and they had developed 0:21:59.840 --> 0:22:04.280 the standard that was called USB one point oh. The 0:22:04.359 --> 0:22:07.080 protocol only gave a hint at what was to come. 0:22:07.119 --> 0:22:11.240 It could transmit data at twelve megabits per second, which 0:22:11.280 --> 0:22:14.680 was much faster than parallel or serial parts, though sluggish 0:22:14.720 --> 0:22:18.840 compared to today's technology. The revised USB one point one 0:22:19.000 --> 0:22:22.359 standard added in another capability of transferring data, but this 0:22:22.440 --> 0:22:27.080 time at one point five megabits per second. So why 0:22:27.080 --> 0:22:31.119 would you lower that quote unquote speed or the capacity 0:22:31.200 --> 0:22:34.640 if you prefer Well, the reason was that some devices 0:22:34.720 --> 0:22:37.560 just couldn't handle a bandwidth of twelve megabits per second. 0:22:37.560 --> 0:22:40.680 They didn't need it. They couldn't handle that much. So 0:22:41.160 --> 0:22:44.399 you needed to have a throttling mechanism in order to 0:22:44.760 --> 0:22:48.119 send data at the proper rate to those peripherals. And 0:22:48.200 --> 0:22:52.359 that was the solution of USB one point one and 0:22:52.560 --> 0:22:55.320 one point one got the most used in those early days, 0:22:55.359 --> 0:22:58.679 not a whole lot of devices UD USB one point oh. 0:22:58.760 --> 0:23:01.600 Almost everyone was using one point one from as soon 0:23:01.640 --> 0:23:04.960 as it was available. It just made more sense. The 0:23:05.040 --> 0:23:08.399 first computer to essue all other ports in favor of 0:23:08.440 --> 0:23:11.760 the new USB standard was the iMac G three In 0:23:13.560 --> 0:23:17.760 so Apple lad the way. It probably comes as as 0:23:17.760 --> 0:23:21.320 a surprise to absolutely no one out there in the audience, 0:23:21.400 --> 0:23:24.679 because Apple is known for dumping legacy systems in favor 0:23:24.760 --> 0:23:27.480 of new technology, at least with their computers, if not 0:23:27.560 --> 0:23:31.240 their mobile devices. Sometimes they hold back with mobile devices, 0:23:31.280 --> 0:23:35.040 but they charge ahead with their computers. So with USB 0:23:35.119 --> 0:23:37.840 devices it wasn't such a big deal since we're talking 0:23:37.880 --> 0:23:42.040 about the universal standard. In other cases, Apple has sometimes 0:23:42.119 --> 0:23:44.959 gone a more proprietary approach, which gets a bit more 0:23:45.000 --> 0:23:48.400 frustrating because that means you invest in a closed off 0:23:48.440 --> 0:23:52.360 ecosystem and you can't really use your equipment with anyone 0:23:52.440 --> 0:23:57.240 else's stuff. In other words, if it's a USB chord, 0:23:58.000 --> 0:24:00.399 you can use that on an Apple product or a 0:24:00.480 --> 0:24:03.800 PC where all sorts of other devices that have USB 0:24:03.960 --> 0:24:06.919