There were two version of the Portable. The original Portable, released 9/89, came equipped with a non-backlit active matrix 1-bit (B&W) display. The second Portable, released 2/91, came with a backlit version of the same display.
In the non-backlit model, upgrades were with 2MB, 4MB, 6MB & 8MB memory cards. In the backlit computers, upgrades were with 1MB, 3MB, 5MB & 7MB cards.
Serial Port with the phone icon supports synchronous modems, with handshaking on both the output and input.