/pub/cbm/documents/projects/rs232/

The lack of real RS-232C interface on the C64 has inspired many people to design their own interfaces and to write instructions how to build them.

c64-uart-1.tar.gz 2009-08-18 48433: André Fachat's RS-232C interface for the Commodore 64, using the 16550A UART.
The board interfaces to the 6581 SID socket. Software is included.
datapump.readme 2009-08-18 406
datapump.sfx 2009-08-18 22962: Directions on making a fast EIA RS 232-C / CCITT V.24 interface to
your C64 using an R6551 ACIA (the same chip as the Swiftlink cartridge
from CMD uses)
datapump2.zip 2009-08-18 12156: A better version of the above by Frank Kontros <jeno@kontr.uzhgorod.ua>.
The schematic diagram is in a GIF file.
rs232-userport-9600.zip 2017-01-25 14290: 9600bps userport RS-232C adapter. Based on the traditional userport
adapter, but with Daniel Dallmann's modification. Schematic diagram
(GIF file) drawn by Frank Kontros <jeno@kontr.uzhgorod.ua>. This is the

UP9600 modification.
rs232-userport.txt 2009-08-18 8183: A schematic to build a cheap RS-232C interface for the c64

with 1488/1489 chips.

Files