Specifications

3 - 8
Note
Many DOS programs use ROM-BIOS display control
functions, or write directly to video RAM. Such software
cannot be used on a serial console device (e.g. ASCII terminal),
with the exception of programs intended to be used with the
DOS ANSI.SYS driver if the terminal is ANSI compatible. On
the other hand, programs which output appropriate terminal
control strings to the console, or which are specifically installed
for the particular serial display device, can be used.
To allow an RS232C serial device connected to either of the two serial ports to be used as a
system console device, use the SETUP utility to select the serial port and configure the appropriate
parameters. As an example, the console output can be set to the primary serial port, 19.2K baud, 8
data bits and 1 stop bit, while the console input can be set to the secondary serial port, 9600 baud,
8 data bits and 1 stop bit.
After booting the system with this configuration, data normally destined for a standard video
display controller and monitor will be routed to the external serial device instead. Keyboard data
will be obtained from both the external serial device and the standard AT keyboard (if present).
Refer to Appendix A for additional information on using SETUP to install the serial driver
options.
Serial Console Cabling and Setup
The serial console device must naturally be set to the same data format as the board's serial port.
Normally, the Little Board/286 serial port's Data Set Ready (DSR) and Clear To Send (CTS) input
handshake signals must be true ("active"), for the ROM-BIOS to send data out. (This hardware
handshake can be disabled with the SETUP utility.) When hardware handshaking is enabled, be
sure to connect the DSR and CTS signal inputs to appropriate handshake signals from the external
serial device's serial interface connector. Alternatively, loop the board's serial output handshake
signals to its input signals as follows: DTR out, to DSR in; RTS out, to CTS in.
3.5.3 Using a Serial Printer
Serial printers can be connected to either of the board's RS232C serial ports as well.
You can instruct DOS to print to the appropriate serial port (COM1 or COM2) instead of to the
Parallel Printer port (LPT1 or LPT2) with the DOS MODE utility. For example, the following
command makes the COM1 serial device become the system's default printer device:
A>MODE LPT1=COM1<Enter>