The 5140 is available in two models. Also included are an Application Selector, SystemApps, Tools, Exploring the IBM PC Convertible, and Diagnostics. The model 22 is the same as the model 2 with Diagnostics only. Both systems can be expanded to a maximum of 512Kb RAM via 128Kb RAM memory card features, and may include an asynchronous modem in the system unit. The IBM PC Convertible Model 003 with a Backlit LCD has internal illumination, which means it can be used in low-light conditions.
Battery life is dependent on the setting of the brightness control.
The Backlit LCD works on all PC Convertible models by plugging it into the LCD assembly, in place of the current screen, and installing the new power supply. A new power supply is packaged with the Backlit LCD Option Kit. At the back of each system unit is an extendable bus interface. Each of these features is powered from the system unit. The CRT Display Adapter operates only when the system is powered from a standard AC Adapter.