You can also install Red Hat Linux/SPARC 4.2using a serial terminal; any terminal which emulates a VT100 ought to work fine. Boot from the floppy, and at the SILO prompt enter:
linux serial
The installation program runs on the first serial port at 9600,8,N,1 (9600 baud, 8 bits, no parity, 1 stop bit). The installation program can run in color, if your serial terminal supports color.
At any prompt dialog during a serial installation (any dialog with an OK button), you can press [Ctrl]-[Z] to start a subshell; to return to the installation program, enter exit at the shell prompt.
When the installation is complete, simply boot normally, and Red Hat Linux should come up on your serial terminal.