In Linux , each serial port is referenced by two device names - one being (for the first serial port) /dev/ttyS0 versus /dev/cua0 . Although these both refer to the same physical port, one important distinction between the way Linux treats these two device names has to do with the DCD line. When ttyS0 is waited on in a system call , Linux assumes that since this device is for receiving telephone calls, it will put a process to sleep — figuring that so long as DCD is low, there is nothing to do. When cua0 is used - as it is when placing telephone calls - Linux assumes that the software needs to access the port while DCD is low for the purpose of dialing the number, so this blocking behavior doesn't exist. Nevertheless, there is a control mode flag called CLOCAL that is what actually activates or deactivates this behavior, and by default the flag is set for cua0 but not for ttyS0. An application that insists on using a "tty" port versus a "cua" port is an example of one that might require a jumper wire to force DCD high in order to work properly. 
The SlimPRO digital low-profile scale’s extra-wide 17-in x -in/43-cm x 37-cm platform accommodates all sizes of patients and the large -in/38-mm high digits on the LCD are easy to read. The SlimPRO’s high 440-lb/200-kg capacity allows for bariatric weighing with an accuracy of -lb/100-g increments. The SlimPRO features a built-in carrying handle for portability, 5-second weight hold, foot pads for weighing on any surface (even carpets), 4 AAA batteries (included), Auto On/Off, pounds-kilograms units switching, easy-to-clean surface, and low-profile -in/36-mm slim depth for easy step-on weighing. The scale’s RS232 serial port allows connectivity with DETECTO’s optional P50 thermal tape printer or EMR/EHR software. With the serial connection, you may print on stable weight or send the data to a PC.