The Jornada 540 series was one of the original models of Pocket PC, when the platform was first announced. Sharing the Operating System, CPU and memory card slot of the 520 series, it featured a 12-bit display (originally advertised as 16-bit display) and USB connectivity. Two models were made available that were identical except for the amount of RAM. The 545 had 16 MB RAM and the 548 had 32 MB RAM.