Altair 8800 connect to the internet ¿?

General discussions related to the Altair 8800 Clone

Re: Altair 8800 connect to the internet ¿?

Postby kwiebe » April 16th, 2019, 8:54 pm

Does the foregoing discussion mean that you couldn't connect a modem to the clone serial port and use it to connect somewhere over analog phone line?

There is a video of an IMSAI doing this. I think he's using CP/M Xmodem to control the modem (no AT command necessary I don't think). Link below.

So, we obviously have CP/M for the clone. I can't tell from this thread whether attaching a modem serially and running Xmodem would succeed as it does with the IMSAI.

https://www.youtube.com/watch?v=nq4g6SLC8NM
-Ken
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Re: Altair 8800 connect to the internet ¿?

Postby TomXP411 » April 17th, 2019, 11:17 am

There's no obvious reason it shouldn't. The only question is which serial port XMODEM is designed to run with. Other communication programs I've found seem to have plugins for different hardware, so you'd just need to set up the system for the 2SIO cards used in the Altair.

no AT command necessary I don't think


Yes, it's necessary... you just don't see it because XMODEM hid that part of the communication. All smart modems have some sort of command interpreter, and even dumb modems still need a way to dial a phone number - my old Commodore modem, for example, used the programmable lines on the User port to trigger different oscillators to send DTMF tones, and the "pulse dialing" mode was even more primitive - the system literally just toggled the "off hook" line repeatedly to dial.

But in the case of terminal servers (that's what a "wifi modem" really is), you must send a string to the terminal server's controller to tell it to connect to a remote host. While most of these devices have adopted the AT standard, some people making homebrew devices may be using something like NodeMCU or MicroPython, which expect Lua or Python scripts.

(In fact, I'm building a terminal server using NodeMCU, just to be different. I haven't done anything with it lately... I really should get back to it and finish that project.)
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Re: Altair 8800 connect to the internet ¿?

Postby kwiebe » April 17th, 2019, 5:28 pm

TomXP411 wrote:But in the case of terminal servers (that's what a "wifi modem" really is)


Thanks. And just so I'm clear, the discussion in this thread with respect to WiModem and connecting to BBS's pertains to IP-accessible BBS's, right?

The choice of device names and terms used to describe things, especially when adapting one protocol to another can hinder understanding. There's just no substitute for a diagram sometimes.
-Ken
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Re: Altair 8800 connect to the internet ¿?

Postby TronDD » April 17th, 2019, 7:24 pm

kwiebe wrote:Thanks. And just so I'm clear, the discussion in this thread with respect to WiModem and connecting to BBS's pertains to IP-accessible BBS's, right?


Yes.
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