Like I said in my other reply, ‘semantic’ errors are not helpful, and are, in fact, one of the reasons why explanations about the ‘analog’ modems are so confusing. Because the word ‘analog’ is used in a special sense.
There is no meaningful difference between the concept of converting between a discretely encoded [partly audible base-band] data stream from a computer into a [discretely encoded partly audible base-band quadrature encoded] […]signal in a telephone modem and …
Yes, when referring to a dialup modem,
‘Analog’ meant it connected to a system designed to handle telephone calls.
However, there is a meaningful difference between the concept of converting a RS232 signal to a V32 signal, and the concept of converting a digital signal to an analog signal.
There are no analog signals on either side of a computer modem.
And
A modem does not convert between an analog and a digital signal
People who are reading about an ‘analog’ modem and a ‘digital’ modem need to be told that those words are just reference labels, and, if necessary, also told that people who say otherwise are using words in a special sense, like Humpty-Dumpty in “Through the Looking Glass”.
I would dispute that. While early versions of Ethernet might be simple enough to be considered pure digital (having only two signal levels and a simple encoding), gigabit Ethernet uses a number of “analog” techniques such as multi-level coding, echo cancellation, adaptive equalization, DC balancing, and Trellis coding. While it’s certainly not as sophisticated as 256-QAM or the like, there’s not much difference between gigabit Ethernet and some types of DSL modulation. I would say the only reason we don’t call Ethernet cards modems is a quirk of history. They meet any literal definition of the term.
I commonly hear the radio which communicates to the mobile network in a phone referred to as a modem, but maybe I only hear that in my head.
So this is my understanding, but as a question, because I’d like to be set straight where I’m wrong. The cellular modem and computer part of a phone are really all smushed together in the SoC package, so they aren’t separate in the way we’d think of a PCMCIA POTS modem being a separate device from a laptop computer.
To the computer part of a phone, the modem is a black box. It sends commands or data, and receives back commands and data. To bring it back around to this thread, many of those commands use the old AT command set originally used on Hayes modems.
Technical sources call it a modem. And if you see a block diagram of an SoC, it’ll be called a modem. But if you ask an average person if their cell phone has a modem… they’ll probably say no.
Your understanding otherwise isn’t wrong, but I will say that from a technical level, a modem in an SoC may still be a black box. Really just a chip that happened to be put together on the same die as some other chips, and with some communication lanes between them. The CPU people may have no idea where the modem lives, whether it’s integrated or hanging off an external bus. And the modem people may also not know if they’re internal or external.
On the other hand, SoCs often share infrastructure between components, such as a memory bus. That’s typical for integrated graphics, as well as things like AI accelerators, though I don’t know if it’s common for modems.
Returning to BBS: You say that they were usually ordinary individuals who hosted BBS from their homes. What happens if, say that you use the same computer and modem to host your BBS and to do all your normal things: You don’t have the BBS running and somebody dials your modem? Do they gain access to everything that’s on your screen (everything that you’re currently running)?
If there is one line and you are using it, they will get a busy signal, though I suppose it’s possible there will be call waiting or something that could make your modem hang up.
If you want them to “gain access to everything that’s on your screen” you need to set that up; pc Anywhere came out in 1986 for example.
Or do you mean, can they tap your line? If it is an individual line and not a party line I don’t see how they can listen to your calls just by dialing your number.
No.
The BBS software shares a specific file structure. If it’s not running, and someone dials your phone number, the modem will ring. If you don’t answer, it will just keep ringing until you do. If you answer the modem (say, with a terminal emulator like White Knight), you can “chat” directly with them, or download files to them.
I’m thinking that there was no internet in the '80s. You could only establish a private connection between yourself and what is probably a computer enthusiast. You were never connected to anything unless you made a connection.
So then wouldn’t your phone line always be free so that someone could dial?
There was internet in the 1980s, but you probably did not have a connection at home and neither did the people dialing up your BBS. They accessed your BBS via a telephone call. If you only had one telephone line and it was always reserved for the BBS, what were you supposed to do if you wanted to order pizza, or receive an important call from your workplace? (We will assume you are not lugging around a Motorola Dynatac or whatever.) The answer is, you paid for an extra line (or 2 or 3 or 4) dedicated to the BBS.
Yes, just like most other hobbies, there were expenses involved. The hardware, possibly software, and an extra phone line or four. Some BBSs charged to get to the good (aka pirated) stuff, or took donations. Others only ran at certain times, so computers and phone lines could be used for other things, but those tended not to last very long.
The home computers running a BBS (so not CompuServe, etc.) were single tasking. If it was running the BBS software, it would answer the phone and accept visitors. If the BBS software wasn’t running, then nothing would happen. WordPerfect does not know how to answer the phone, and there is nothing running in the background to handle it. (DESQview and some other things sort of allowed BBS software to run in the background, but it wasn’t anything like a modern multitasking OS.)
Now that I think of it I realize that my question is like asking, ‘Why when I type google.com in my search bar and press ENTER do I not gain full control of Google?’
I think anytime you connect to a server or host, you do so by way of a protocol; you begin a TCP/IP session with that computer.