It's only slightly related, but I had this thought about setting up a wireless alternative to old BBS systems using only WiFi hotspots without an Internet connection.
That's awesome! I've been kicking around some ideas in this space, but it's just a pipe dream at this point. Alternative means of communication are interesting.
I love seeing the ESP8266 at the heart of this project. This little chip is the sweet spot - if you are new to the chip I would check out the videos by CNLohr on YouTube.
But this device is out of stock. Anyone hunted down schematics or firmware source for this device?
I've used the ESP8266 for a few things, and honestly its just such a lovely little device with great support, I don't know why it doesn't just get used everywhere.
Some of the emulators for older computers provide similar functionality.
The VICE Commodore computer emulator can use an external program called TCPSer to provide an emulated Commodore PC with a virtual modem. The command ATDT ip-address:port can be used to connect to telnet-ready or vanilla-TCP BBS's with vintage terminal software.
Tried finding the spec for modulating/demodulating recently and came up empty. I wanted to write a useless phone app that sends and receives data by way of the old audio, two-tones, (modem) format.
Anyone have any pointers?
[Edit: reading other comments, probably I want to look into "v.32bis", etc.]
Keep in mind, if you plan on doing this to dial into other modems, many phone contracts explicitly prohibit using a phone call for anything other than voice.
That doesn't mean I'm not gonna try hooking up my old hayes compatible, but I'm on prepaid so I don't have to care.
The starting point is probably V.21 / Bell 103. Check out the datasheet for the AMI S3531 single-chip modem, it's got useful background and timing info.
For me, calling a BBS will always be a modem and modem tones. I would like this more if there was a way to open a TCP connection directly to the BBS and somehow do v.32bis tones over IP. This would constrain the connection to actual modem speeds and wouldn't require a PSTN line or a VoIP provider. It would be similar to VoIP except using a codec that was specifically designed to make those legacy modulation schemes work. Ideally, this wouldn't require a real modem but if you could use a real modem and a FXS device, that would be sweet, too.
It's definitely possible to add a small piezo speaker to the board and have it play a recording of the sound to you when you open a new telnet connection ;)
In a similar vein, years ago I designed a "digital extension cable" that communicated by modem. The point of the device was to replicate the state of 4 inputs at a water pump station to a remote monitoring site a few miles away. The box I built scanned the inputs about once per second, and if there was a state change, called the remote site over a leased phone line where an identical box had 4 outputs that replicated the state.
It turned out to be much faster to make the call at 1,200 bps than at the 57.6kbps max speed of the modem.
At the high baud rates, the time the modems took just to negotiate the connection and agree on a speed (about 5-10 seconds) was far longer than it took to transmit the few bytes of data at 1,200 bps and disconnect (well under 1 second). At 1200 bps, there was no negotiation: the communication is based on FSK at fixed frequencies.
One of those weird things I mentally filed away a long time ago :-)
https://www.joeldare.com/blog/post/wireless-bbs/