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These are C64 cartridges made by Richvale Telecommunications from Richmond Hill, Ontario, Canada. They provide the C64 with an IEEE interface for connecting the older 4040, 8050 drives etc.
The RTC V-Link "64" appears to be an early or pre-production version of the C64 Link. There was also a V-Link for the VIC-20 computer. I am not sure which one was first. Created in 1982, it offered an IEEE connector and BASIC 4 extensions.
This unit belongs to Walter M and his pictures are included with permission.
The RTC C64-Link is based on the V-Link and appears to use the same pcb, but seems to be a little more finished. Created in 1982, it offered an IEEE connector and BASIC 4 extensions.
Download EPROM firmware here (caution: not verified).
This unit belongs to to me.
The RTC C64-Link II was the followup version, released in 1984. It offers an IEEE connector, "link" connector and BASIC 4 extensions. The link connector was used for networking multiple machines together.
Manual available here. Download EPROM firmware here.
More pictures (Nov'23): 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9
This unit belongs to to me. I have removed the components and scanned the pcb.
I am hoping to reverse-engineer these RTC Link carts. I am starting with the Link-II cart. The first is a straight clone. I scanned the bare PCB front and back and loaded them into KiCad. Then I placed the components and created a board outline to match the real board. I could then follow the traces and create a schematic. I routed the traces as closely as possible. Note that the original Link-II cart has components on both sides in order to keep the PCB as small as possible and to fit inside an AMP connector shell.
The second board is a re-make with some changes. I call it "RTC Link-II+". This version has all the components on one side to make it easier to assemble. In order to keep the PCB small I have replaced the DIP EPROM with a PLLC and also used a resistor network in place of some resistors. In this way the PCB is exactly the same size as the original. Since the PLCC EPROM is of a larger capacity I added a jumper that can select between two firmwares. I modded the firmware of one to change the power-on message to "RTC C64 BASIC V4" but in the future it could be possible to install a different modded firmware with other changes.
Both these designs are available on Github here: RTC-Links.
Created: Jan 28/2012. Last updated: Apr 5/2025, 11:30pm EST
Send comments or feedback to Steve Gray(sjgray@rogers.com)
