The ‘Simple’ Wifi Modem it’s a device to connect a computer with an RS232 serial port to a telnet BBS. It does not use an analog phone line but internet through a wifi connection. Behaves like a Hayes dial-up modem, and it is designed and built for old computers; i use it with my first computer ever (still working!): a Sinclair Zx Spectrum and, being myself a retro-collector, also with a lot of other different machines (you can read about my collection on www.museo-computer.it. My idea was to create a device with the same look and feel of a real modem: a lot of big, flashing, red LEDs and only a few SMD components.
In this second release i've redesigned it to implement full hardware flow control, optimized the circuit and switched a couple of components to smd.
Main characteristics:
- Emulation of a Hayes modem
- DB25 serial connector
- Uses 5v micro USB cable port for power
- LEDs for status, as in old modems
- Hardware flow control
The software installed is a fork of Zimodem written by Bo Zimmerman https://github.com/bozimmerman/Zimodem. It has just been modified to support this device.
if you don't want to build it by yourself i sold it fully assembled and tested on ebay (search for "Simple Wifi RS232 Modem") and on Etsy. I build batches of that so maybe it will not be ever available.
Using the Simple Wifi Modem
Plug it into an RS232 DB25 port (or, through an adapter, into a 9 pin serial) and power it connecting a standard micro usb cable to a USB port capable of providing at least 100mA at 5v DC.
The device will turn on the Power LED (and CTS led if RTS/CTS flow control is set).
Power on your computer and launch an ASCII terminal program and set the baud rate to 1200.
If you now type ATI you must see the welcome message.
To configure it use the command AT+CONFIG, follow the instructions and connect to a wireless router.
When connected you can dial in to a bbs using ATDT [HOSTNAME]:[PORT]
This is the complete list of commands available.
Firmware upgrade
If needed you can upgrade the modem firmware or install whatever software you want. You can do in multiple ways.
These are the complete instructions to load a firmware on the Simple Wifi RS232 modem.