Keysight E8402A, E8404A C-Size Mainframes User and Service Guide 23Configuring Your Mainframe Getting StartedRS-232 InterfaceThe RS-232 interface on the rear panel of the Enhanced Monitor mainframes(Keysight E8402 and E8404) can be used to control the Enhanced Monitor from acomputer or a terminal.Refer to Chapter 3 for RS-232 programming information. TheSYSTem:COMMunicate:SERial ... commands set and/or modify the configurationof the Enhanced Monitor's serial interface. Serial communication commandstake effect after the end of the program message containing the command(s).Default RS-232 parameters are:– Baud: 9600– Bits: 8– Parity: None– Stop bits: 1– DTR/RTS: On– Pace: XON– Echo: On– ERES: On– Line buffer: OnExternal +5V SupplyThe External +5V supply is for powering the Enhanced Monitor (including theRS-232 interface) while the mainframe is powered down (standby mode). Thisrequires a stable 5 volt supply capable of 1.5A amps maximum (500mA typical,refer to specifications in Appendix A). Refer to Figure 4.If you use the Enhanced Monitor RS-232 interface (located on theback of the mainframe) while the mainframe is in the standbymode, you must supply an external +5Vdc to the +5VEXTconnector (located near the RS-232 interface). If you use theRS-232 interface while the mainframe is powered on, you do notneed to provide the external +5Vdc.
