The XR16L2551 (L2551) is a low voltage dual universal asynchronous receiver and transmitter (UART) with 5 Volt tolerant inputs. The device includes additional capability over the ST16C2550: Intel and Motorola data bus interface selection, hardware and software flow control, infrared encoder/ decoder, sleep mode and a PowerSave mode for battery operation. The L2551's enhanced register set is compatible to the ST16C2550 and XR16L2550. It supports the Exar's enhanced features of 16 bytes of TX and RX FIFOs and a complete modem interface. Onboard registers provide the user with operational status and data error tags. An internal loopback capability allows onboard diagnostics. Independent programmable baud rate generator is provided in each channel to support data rates up to 3.125 Mbps. NOTE: