In 1981 Rockwell released an improved model of it's popular AIM-65 computer, the AIM-65/40. The Rockwell AIM-65/40 is a single board computer that features system address of up to 128KByte, with 48KByte onboard memory. It is built around the Rockwell R6502 processor (MOS 6502 compatible) and a full ASCII keyboard. The machine was also equiped with an RS-232C interface, two user-definable 8-bit parallel ports with handshake, two 16-bit timer/counters, and an 8-bit serial shift register. Three additional 8-bit parallel ports were directly programmable to privide TTL level I/O, or interfaces to keybaords, displays and/or printers.