Yes, RS-232 is a serial port (digital). What does that have to do with VGA (D-sub)?
Yes, RS-232 is a serial port (digital). What does that have to do with VGA (D-sub)?
BaHahahahahahahaha rbmorse!! Thank you HippsieGypsie ^5
rbmorse? Where in that description do you see the verbiage DIGITAL? No such animal existed back in the days of Mainframes, nor VGA, or SVGA monitors! It was ALL analog! That's sort of like stating an RJ11 is a digital connection, whereas it isn't.
Then why did you tell John, after he said tried the D-sub video port (which is VGA), that he was wrong and that he had to try a display with an analog connection? In my #57 I you that the D-sub (VGA) was an analog connection. You agreed in your #58, maybe without realizing it, but then you introduced the bogus term "serial video" in reference to an analog video connection.
Now, I'm still looking for an analog video connection called a "serial video," but it's hard to find things that don't exist. Do you know why it doesn't exist? No, of course not otherwise we would not be having this discussion. There's no such thing as an analog "serial video" because the term "serial" describes a digital protocol.
Hippyegypsey doesn't understand the difference between analog and digital. Let me quote from the very first sentence of the Wikipedia article he linked:
This is a description of a digital process. Analog does not deal in "bits." Or, maybe you don't know that.In computing, a serial port is a serial communication physical interface through which information transfers in or out one bit at a time
As for digital displays not being around in the days of mainframes, VGA, SVGA. I guess you need to learn that both the IBM Monochrome and CGA video adapters used in the original model 5150 PC used a digital TTL+I (intensity bit -- oops, there's that digital word "bit" again) interconnect between the display adapter and the monitor. EGA was TTL+I digital, too. All of those predate VGA and SVGA. The IBM DisplayWriter, the DecMate and Wang Personal Word Processor, all of which came before the PC, had digital TTL+I connections to their displays, too. So did the Data General Eagle 1. And the IBM Model 360 (well, sort of. You needed a separate minicomputer (model 2250) to generate a visual display with the 360).
Oh...the RJ-11 standard describes a telephone jack. Not a communications protocol. But, you probably didn't know that either.
Just my 2 cents. This was from another website "
If it's a flat screen monitor, it is digital. If it's a big square block, it's analog.
As for the signal, if it's a 15-pin VGA trapezoidal plug, it's analog, if it's a long rectangular DVI plug, it's digital. On that Dell, you probably have VGA built into the motherboard. An option for that computer is an upgrade to a video card that would have both analog (VGA) and digital (DVI) plugs" Not that's a different machine, but my BenQ has both inputs, and the video card has the same two inputs.
rbmorse. let me explain to you. I'll use small words so you can understand. Serial communication was something that was WAY back in the days when a dial up modem used a 9600 thru 28800 baud rate modem, to change the telephone signal to bits, the stream ran serial communications as in ones (1) and zeros (0), which you probably know as binary, a modem (serial type) had to speak to the computer in MACHINE language. Here is a good reference to that as well. In telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels. Serial communication is used for all long-haul communication and most computer networks, where the cost of cable and synchronization difficulties make parallel communication impractical. Serial computer buses are becoming more common even at shorter distances, as improved signal integrity and transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity (no need for serializer and deserializer, or SerDes) and to outstrip its disadvantages (clock skew, interconnect density). I know this prehistoric way of communication is odd to you, seeing as you probably have had a high speed connection your entire computing life. Let me further state the list below are various connections, so you are clear an analog connection uses a twisted pairs. Please exam the list below, you will get a written test to complete on Monday, a 1/3 of this semester's grading will result from your score.
Morse code telegraphy <<< Can you say this is digital?? LoL...It's the original analog!!
RS-232 (low-speed, implemented by serial ports)
ARINC 818 Avionics Digital Video Bus
Atari SIO (Joe Decuir credits his work on Atari SIO as the basis of USB)
Universal Serial Bus (moderate-speed, for connecting peripherals to computers)
Fibre Channel (high-speed, for connecting computers to mass storage devices)
InfiniBand (very high speed, broadly comparable in scope to PCI)
MIDI control of electronic musical instruments
DMX512 control of theatrical lighting
SDI-12 industrial sensor protocol
Serial Attached SCSI
SpaceWire Spacecraft communication network
SONET and SDH (high speed telecommunication over optical fibers)
T-1, E-1 and variants (high speed telecommunication over copper pairs)
That's probably true now, but at one time there were VGA/SVGA analog flat panel displays. I had a Sony like that. Viewsonic made a couple, too. They had an adjustment for '"phase" and another for "shaprness" that were supposed to reduce ghosting and other artifacts. I dumped it for a digital display the first chance I had.
There used to be CRTs (the square boxes) with digital interfaces, too. I mentioned the IBM Monochrome, CGA and EGA displays above. They used a digital connection to the PC and all the signal processing was digital right up to the rasterization of the final output.
rbmorse said:OML! hahahahahahhahahaha BIG time WRONG, here you go sonny. Rasterization is the process of converting a vertex representation to a pixel representation; rasterization is also called scan conversion. Included in this definition are geometric objects such as circles where you are given a center and radius. In these notes I will cover:There used to be CRTs (the square boxes) with digital interfaces, too. I mentioned the IBM Monochrome, CGA and EGA displays above. They used a digital connection to the PC and all the signal processing was digital right up to the rasterization of the final output.
- The digital differential analyzer (DDA) which introduces the basic concepts for rasterization.
- Bresenham's algorithm which improves on the DDA.
- The scan line fill for polygons.
- And, time permitting, flood and boundary fill algorithms.
Scan conversion algorithms use incremental methods that exploit coherence. An incremental method computes a new value quickly from an old value, rather than computing the new value from scratch, which can often be slow. Coherence in space or time is the term used to denote that nearby objects (e.g., pixels) have qualities similar to the current object.
Now onto analog. The traditional type of color display screen that has been used for years in televisions. In reality, all monitors based on CRT technology (that is, all monitors except flat-panel displays) are analog. Some monitors, however, are called digital monitors because they accept digital signals from the video adapter. EGA monitors, for example, must be digital because the EGA standard specifies digital signals. Digital monitors must nevertheless translate the signals into an analog form before displaying images. Some monitors can accept both digital and analog signals. Some analog monitors are also called digital because they support digital controls for adjusting the display. Would you like for me to go into further detail on either subject? Now rbmorse, are EGA monitors still available? Or were they replaced with VGA, then from there SVGA monitors.
Mike, your ignorance is boundless.
You know that your standard telephone service is still analog to the local switch (or PBX if you have one of those, or the local interface if you're on cable or FIOS). You know how touch tone(tm) works, right? Makes little analog tones when you push the buttons to tell the switch which number to connect. Perhaps you still amuse yourself by trying to play tunes with the keypad on the telephone set?
Well, guess what? Modems work the same way! It's true! A modem takes the digital signal from a PC's serial port (rs-9 or rs-232), converts it an analog signal for transmission over the telephone network (if you've ever picked up an extension while a modem was using the line you heard it "sing." The "connect tones" modems send when trying to negotiate connection parameters with a modem on the other end are all analog signalling. On the other end of the connection, the other modem converts the analog input from the tel line back to a digital signal and sends it on to the receiving PC via a serial communications port (rs-9 or rs-232).
Every one of the standards you listed is a digital communications protocol, no argument there. I'm not sure what that has to do with PC video. I'm still waiting for a standard for an analog serial video port, which you said was common usage. I can't find it. Please help me out of my ignorance.
Well rbmorse, don't say I never helped you out! LoL here ya go Lesson 04: Analog Read Serial Port : Arduino Course for Absolute Beginners - YouTube that should explain the simplistic principals, and go into more detail, as you go thru each lesson in this series.
re your #67
That's exactly what I said. At at some point you have to convert the digital cideo signal to an analog form that a CRT presents on the front of the tube. That process is caller rasterization. And yes, all CRT's are analog at the stage where they produce the final output.
What does this have to do with PC video communications protocols? I'm still waiting for a description of the commonly used analog serial video connection.