Build your own “Strikelink” C64 User Port -> USB device for less than $15!

The least expensive way to get your C64 online is by building what I call a “Strikelink”, which is basically just a null modem that converts TTL signals to rs232 and vice versa. The parts listed below will allow you to hook your c64 to any usb port on a pc. Software on the PC side makes the “Strikelink” act as a virtual hayes modem at 2400 baud!

You’ll need a ch340g -> Serial/USB Device. You can find them on ebay for a few bucks. For 9600 baud, you’ll need to solder directly to the chip’s rts and cts lines, or find a ch340g -> usb with direct rts/cts out pins.

and this

Connect the TxD pin on the TTL Adapter to pins B and C on the User Port plug (RxD). Connect the RxD pin on the TTL adapter to pin M on the User Port plug (TxD). And connect the GND pin on the TTL adapter to pin N (Signal Ground) on the User Port plug. Install the driver, load up Leif Bloomquist’s BBS Server, and now you have a 2400 baud modem for $15 or less.

To add full 9600 baud capability

Add a wire from M to 5 on user port plug
Add a wire from B,C to 7 on user port plug
Attached a wire from L to 6 on the user port plug

Add the rts/cts lines to the ch340g from the user port (user port rts -> ch340g cts and user port cts -> ch340g rts)

Then use the UP9600 driver on Striketerm or CCGMS 2017

Use the instructions in the Connecting to C64 BBSes section on the left and look for the heading Using StrikeLink or other TTL/Serial Adapter/swiftlink/turbo232 (to use your PC as a virtual hayes modem)

Refer to for a diagram of the C64 User Port



18 thoughts on “Build your own “Strikelink” C64 User Port -> USB device for less than $15!

  1. I’ve ordered all the parts to make a Strikelink that i want to use with my Vic. I currently use Striketerm with my Swiftlink on the 64 with tscser for the faster speeds. This method uses a nul modem cable from the swiftlink to the PC.

    Is using the Strikelink method is it just VIC/Strikelink/USB to USB on the PC?

  2. Just and update on the Strikelink. It works on both the 64 and Vic-20. I have had problems with the data just stopping. On the 64 I can be downloading an entire disk without any problem and the next one it will just stop midway through. Same issue on the Vic-20 it will stop just reading a BBS e-mail. It may be a driver/setting issue that I have yet to figure out.

    • I may build a couple if there’s enough demand. Though the ez232 is only $30 from doppleganger, and I believe he has some in stock. That will allow you to connect at 9600 baud. Check the appendix of the Striketerm Documentation for his info.

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  4. So I bult the upgraded version and no dice. I have verified all connections and while tcpser sees what I am typing the computer gets nothing back. Andy ideas?

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