How-To get a Commodore C64 connecting over telnet to you favorite BBS

Hello fellow nerds, this a short description on how to build a null modem for your C64, connect it to a Raspberry Pi with a USB TTL RS232 serial port and connect via internet to your favorite telnet BBS.

What you need

A Raspberry Pi or some other computer with USB-ports, and a USB TTL-level RS232 serial port dongle. In my case i bought the cheap-o-version from eBay:

And also you will need an edge connector for your modem-port on the C64, and in my case i bought these:

Obviously you will need some soldering skills for this to work as well.

You will also need a good BBS-terminal software for the C64 or C128. Some are able to be URL aware already, others only know phone-numbers. But the "tcpser" tool is able to map phone-numbers to URLs and ports.

Building the cable

I do not take ANY responsibility if you mess things up here.

I used this guide:

I took a non-destructive approach to my build. Where I cut three breadboard (the male version) and soldered them to the edge-connectors pins and labeled them accordingly:

  • Label to TOP-side of the connector with TOP
  • Solder a bridge wire between pin 12 and 1
  • Black breadboard wire from 12
  • Green wire from 11 & 10
  • White wire from 2

Connect them to the corresponding GND/TXD/RXD on the USB-dongle's female connectors (if you bought the same as I)

Slab a some tape around the edge connector so that you don't short any other pins over the coming years, we need to keep our C64's safe!

Setting up your Raspberry Pi

Just install Raspbian GNU/Linux and make sure that the machine reach the internet, and then install the tool called "tcpser"

Getting on-line

Fire up "tcpser" on your RaspberryPi like so:

$ tcpser -d /dev/ttyUSB0 -s 2400 -tsS

Start with a low boad-rate and work your way up to find your max.

The start up the terminal program on your C64 (in my case I use the cool StrikerTerm which is fairly new and quite potent).

Try something out! I would recommend Frozen Floppy at:


Back to the index:

Kind regards,

Your nerd friend AiO