Link232 is a early RETRO Innovations project that was designed in 2007. Initially, we planned to replicate the exactly functionality of the CMD Turbo232. However, since the T232 required programmable logic devices to support 100% functionality, we decided to simplify the design and support SwiftLink compatibility. As the Swiftlink is a relatively simple design, replicating the functionality was not a difficult process. We took the opportunity to improve on the design in 1 small way: memory mapping. While the original Swiftlink claimed all 256 locations in the IO memory map of the C64/C128, the Link232 reduces that to 16 locations and allows the user to select which 16 byte "bank" will be used. As all existing Swiftlink software will expect the device to reside in the lowest bank, we don't expect the bank selection systems to be utilized much, but it does allow other cartridges to reside in the rest of the address space.
Unlike later RETRO Innovations projects, we did not produce this unit ourselves, but placed the design files online for others to produce.
Link232 requires an open cartridge slot on a C64, SX64, C65, C128, C128D, or C128DCR machine. It also requires a DB9 cable that carries RS232 traffic from a modem or another computer system.
Currently, Link232 devices are not available from RETRO Innovations. However, RETRO Innovations is working on a new version of this cartridge design that will include complete Turbo232 functionality.
EAGLE Schematic and PCB files are available here.