Ports primer
Hi again Helz15![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Ok, let's see if we can get you up to speed with a sort of "computer ports primer"... *very deep breath*
First detail in case you didn't know it: all the ports described here use digital signals of one form or another, rather than analogue. I trust you understand this ok so I won't go into it further here.
RS-232 is the electrical standard used on computer "serial ports", aka "com ports". So the terms are often (perhaps wrongly?) used interchangeably. Most computers will have 2, 1, or maybe 0 (on very modern ones) serial ports! If you have any 9 pin "D-plugs" (see later images) around the back of your computer, probably next to your "parallel port", those would be serial ports. Note that the 2nd serial ports of some MUCH older computers have 25 pins instead, which can make those ones quite easy to confuse with the parallel port
To interface with a serial port, it's easiest to use the MAX232 (or similar) chips mentioned, because RS232 uses quite odd voltages and these chips convert those signals to and from the 0/5V ones we often prefer to use in our circuits. Serial ports have few signal lines: one in either direction for data, which is sent 1 bit at a time, and some others for such details as "flow control". They used to be used for modems, and occasionally for mice.
As you guessed, yes: "parallel ports" are one of the various ones whose connectors have the screws in. They're 25-pin D plugs, and their main use is in connecting (older) printers to the computer, so they're usually just called "printer ports". I mentioned that some very old computers also have 25-pin serial ports- if you have one (you'll see illustrated further on) then you can tell them apart by the gender of the connectors. My own personal, subjective and very very limited experience of interfacing circuits with parallel ports was not too great, but other people have managed ok and plenty of commercial hardware used to use them happily for all sorts of things. There's good reasons why my experience was quite probably irrelevant. Parallel ports use either 0-5V, or 0-3.3V signals (never heard of any other levels but I could be wrong). They have quite a few signal lines, mostly from the computer to the device (because they're mostly for printers).
WHAT THEY LOOK LIKE:
If you have a relatively modern computer with these ports, it should look a bit like this: **broken link removed**
(colours may vary?) Note that the TOP one there is the "parallel port" or "printer port", hence the printer icon. The other two smaller ones are the serial ports, hence the little "binary stream" icons next to them. That coverplate there ALSO has an icon for "monitor" next to one, because they make such plates for lots of different motherboards, and some would have a different connector there!
But VGA monitor sockets do look different enough if you look properly, and you couldn't fit a serial plug into one, so no worries. Eh, unless you bought the wrong type of plug too ![Roll Eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
If you have a MUCH older computer, your serial ports will probably look like on this page: https://computer.howstuffworks.com/serial-port2.htm
But that's quite a big "if"
Obviously though, merely having backplates like that (which almost all PCs have) but with other connectors on them, doesn't mean that those connectors are old serial ports!
(Sorry if that sounds too obvious)
As I said, I think SOME new computers don't have ANY RS232 serial ports, and maybe no parallel printer ports either!
USB is a very different sort of serial port (actually a "bus") that is replacing them for most new commercial hardware. But it's much harder (not impossible!) for hobbyists like us to work with
If you have only USB, and no serial(RS232) or parallel ports at all, you should let us know so we can help figure out what options are available to you. But it sounds as though you do have some anyway??
Ok, sorry that was so very long (maybe I should copy it to a page of my site for future), but it did sound like these details were new to you. Hope it helped!![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Hi again Helz15
Ok, let's see if we can get you up to speed with a sort of "computer ports primer"... *very deep breath*
First detail in case you didn't know it: all the ports described here use digital signals of one form or another, rather than analogue. I trust you understand this ok so I won't go into it further here.
RS-232 is the electrical standard used on computer "serial ports", aka "com ports". So the terms are often (perhaps wrongly?) used interchangeably. Most computers will have 2, 1, or maybe 0 (on very modern ones) serial ports! If you have any 9 pin "D-plugs" (see later images) around the back of your computer, probably next to your "parallel port", those would be serial ports. Note that the 2nd serial ports of some MUCH older computers have 25 pins instead, which can make those ones quite easy to confuse with the parallel port
As you guessed, yes: "parallel ports" are one of the various ones whose connectors have the screws in. They're 25-pin D plugs, and their main use is in connecting (older) printers to the computer, so they're usually just called "printer ports". I mentioned that some very old computers also have 25-pin serial ports- if you have one (you'll see illustrated further on) then you can tell them apart by the gender of the connectors. My own personal, subjective and very very limited experience of interfacing circuits with parallel ports was not too great, but other people have managed ok and plenty of commercial hardware used to use them happily for all sorts of things. There's good reasons why my experience was quite probably irrelevant. Parallel ports use either 0-5V, or 0-3.3V signals (never heard of any other levels but I could be wrong). They have quite a few signal lines, mostly from the computer to the device (because they're mostly for printers).
WHAT THEY LOOK LIKE:
If you have a relatively modern computer with these ports, it should look a bit like this: **broken link removed**
(colours may vary?) Note that the TOP one there is the "parallel port" or "printer port", hence the printer icon. The other two smaller ones are the serial ports, hence the little "binary stream" icons next to them. That coverplate there ALSO has an icon for "monitor" next to one, because they make such plates for lots of different motherboards, and some would have a different connector there!
If you have a MUCH older computer, your serial ports will probably look like on this page: https://computer.howstuffworks.com/serial-port2.htm
But that's quite a big "if"
As I said, I think SOME new computers don't have ANY RS232 serial ports, and maybe no parallel printer ports either!
Ok, sorry that was so very long (maybe I should copy it to a page of my site for future), but it did sound like these details were new to you. Hope it helped!