We are using an Analog Devices ADuC832 device and we have observed that the C51S.lib works well for printing to the serial port under the small memory model. We have not had any luck generating output from the serial port using C51L.lib however. It compiles under the large memory model so we are not sure why the output is garbage. What could cause this? Could this be related to STARTUP.A51? Has anyone else had success with I/O under the large memory model? Thanks in advance, Brian Chase