This group of work group servers have a feature called "Advanced Lights Out Manager (ALOM)".
http://sunsolve.sun.com/handbook_pub/validateUser.do?target=Systems/SunFireV490_R/spec
The ALOM feature on servers like the V490 is enabled through a "System Card (SC)" which even offers a windows GUI through the "Sun Remote System Control (RSC)"
- http://www.sun.com/servers/rsc.html
The "Sun-Fire V490 Server Administration Guide" covers features with the System Card, basic setup, and basic usage
- http://docs.filibeto.org/products-n-solutions/hardware/docs/pdf/817-3951-11.pdf
(Pages: 22,33-35,54-55,72,73-78,83-84,99,101-102,122,125,141,159-161,168-169,172,175,181-182,190-197)
Specific case usage is covered in the "Sun Remote System Control (RSC) 2.2 User’s Guide"
- http://dlc.sun.com/pdf/816-3314-10/816-3314-10.pdf
The latest version of the software is 2.3.3, installation examples can be seen here.
- http://www.sun.com/servers/rsc_download_readme.html
You can check to see if a platform appears to have an ALOM card installed.
- {system}/{user}$ prtfru -x | nawk '/Container name="rsc-board"/,/Container> /'
You can check to see if supplemental OS software is installed on this server.
- {system}/{user}$ /usr/bin/pkginfo | grep SUNWrsc
By attaching to the ALOM on the SC through the RSC GUI, TCP/IP telnet/ssh, serial terminal server, or even dial-up modem - support staff has access to OpenBoot Firmware on the platform before the boot, can initiate alternate boots, enable debugging, completely power off & on the entire chassis, and even disable failed components (like memory chips) on some models remotely.