Two main models were released. The model 'A' had display to either a TV or a monitor. The model 'AD' also included a one-line, 16-character, vacuum fluorescent (VF) display on the unit which permitted operation with or without a TV screen or monitor — the VF display responded to the cursor keys and scrolled around the screen display area. One additional model was released, but this was a custom version for a pharmaceutical chain, with no screen display — only the VF display — and was not widely known.