4800 HD (250-3539) Options Faxback Doc. # 1417 * Ni-Cad Battery Pack (25-3541). With a fully charged battery, you can power the computer for about 2.5 hours from a fully charged battery. The maximum operation time varies depending on the options you install, the backlight brightness, and the amount of diskette and hard drive access. * Internal fax/modem that operates as 2,400 bps and has MNP-5 error correction (25-3542). The fax can send and receive at 9,600 bps. The modem port is identified as COM2. Some applications ask for this information before you can use the modem. * Internal Micro-Trackball (25-3545) The trackball replaces the panel above the left end of the keyboard. A trackball functions like a mouse. However, instead of rolling the trackball over a surface, you move your finger across the trackball to position the pointer. * External Keyboard (26-4032). You can connect an external keyboard to your computer's built-in external keyboard port. The built-in keyboard remains active even when an external keyboard is connected to your computer. *External Monitor. You can connect a VGA monitor to your computer's built-in video port. The system comes with display utilities that let you switch between viewing the internal display, an external monitor or both.