0Hi,
Although I've been putting Sun systems on PC-style PS/2 KVM switches for
years at work, I recently went a few rounds of this at home. I had some
failures, as well as successes, so I thought I'd post the results. At the
very least, this will get into Google and help the next person who tries
this.

The two high-level things you must do to hook your Sun to a PC KVM switch
are:
1) Adapt the video for PC-style connections, resolution and refresh rate.
2) Adapt the Sun keyboard/mouse connections to something the KVM switch
uses, either USB or PS/2.

I bought a used Apex Outlook EL-80DT KVM for home, which uses PS/2
connections, so that's what I concentrated on. Further, the machines I'm
using made 1) pretty easy, so this note focuses on achieving 2).

I have an Ultra10 with built-in PGX24 graphics and an E250 server with a
PGX32 card. (The Ultra10 actually has a Creator card in it but I don't yet
have the 13W3 to VGA adapter for it, so I'm using the PGX24 for the time
being.) Therefore, no special video cabling was required, since both PGX
boards have standard VGA (HD15) connectors. Also, both of these machines
are non-USB machines, and they have the old, proprietary Sun keyboard/mouse
connectors.

The best way to hook these systems to a PS/2 KVM switch is by using the Sun
Interface Converter. This device used to sell for US$75 from SunStore and
adapts the Sun kbd/mouse to PS/2 connectors. The option number was 465A
and the part number was 595-3692. However as of sometime in 2003, Sun
seems to have discontinued this device, probably since no current machines
have the old kbd/mouse connector. If you can find these at a surplus site
or from eBay, they're worth the money for the simplicity of hooking your
older Sun machine to a KVM switch. [Note to Sun: now that this device is
obsolete, it might be nice to "GPL" the design of this adapter to benefit
the many Sun hobbyists around the world.]

However all is not lost if you cannot get the Interface Converter. You can

use commodity USB PCI cards and USB-to-PS/2 adapters to connect the system
to a KVM switch. This allows you to use the system under X (CDE or
OpenWindows) ONLY, however. There is no OBP access thru the USB
adapter; you will need to hook up a serial console when you need OBP access.

Here's what I did to use a USB-to-PS/2 adapter to connect my Suns to a KVM
switch. Both Suns are running Solaris 8, but the process is the same for
Solaris 9.

1) Update OBP to the latest release for your system(s).
2) PATCH your Solaris 8 (or 9) system with the latest USB framework patch
109896 (115553 for Solaris 9), Xsun patch 108652 (112785 for Solaris 9), and
the latest patch for whichever graphics adapter you're using. You need to
reboot after applying these patches.
3) Get a supported USB card for each Sun. I recommend USB 2.0 cards using
the NEC D720100AGM chip; whatever board you get, make sure the chipset
is supported by the native Solaris USB drivers. I've been able to find
5-port cards with the NEC chip for about US$25 apiece, sold under
several lesser-known brand names at bricks-and-mortar retailers. Install
the card and do a 'boot -r' to update the device tree.
4) Get a USB-to-PS/2 adapter for each Sun. This is a little tricky: there
are many of these adapters out there, and many of them don't currently work
(as of May, 2004). Of course, future patches could fix bugs and might
enable the other models to work. The only one that worked for me is
the Inland USB to PS/2 converter, stock # 08315 (see
http://www.bencole.com/singleproduct...partnum=08315).
Adapters I tried that do NOT work are the QVS model USB-PS2Y (rev. 3 and
3GW) and Belkin F5U119-E. I also saw a Compaq-branded model that looked
identical to the QVS, but I didn't try it; I assume it's a re-branded QVS
and would not work either. [For the infinitely curious, the USB VID/DID for
the Inland model is 0x518/0x1, in case you are able to find this unit sold
under a different name. Also, it appears in syslog with the identifier
"Composite USB PS2 Converter USB to PS2 Adaptor v1.09".]
5) While using a serial console or a true Sun kbd., boot the system and
connect the USB-to-PS/2 adapter. This will create device entries under
/dev/usb for the keyboard and mouse devices. You need the serial console or
true keyboard for the following step.
6) Follow the instructions in Infodoc 72414 or in the USB Dual Framework
whitepaper
(http://www.sun.com/desktop/whitepape...Whitepaper.pdf) for
updating /etc/system to configure the system to use a USB mouse and
keyboard. Be careful updating your /etc/system as it's a very sensitive
file.
7) Delay CDE's startup on future reboots to make sure the USB kbd/mouse
have initialized. Do this by moving /etc/rc2.d/S99dtlogin to
/etc/rc3.d/S99dtlogin.
8) Shutdown the system, cable it to the KVM, and boot back up. You can
leave the serial console connected if you wish. Note that the USB-to-PS/2
adapter must always go in the same USB port. If you need to move it, you'll
need to update the mouse and keyboard paths in /etc/system again.
9) Be patient when booting. The CDE login screen won't appear on the
monitor until the machine is fully booted. And until the login screen
appears, you may only have a blank screen.

That's it, you're done!

Regarding USB KVM switches...
I have not tried any USB KVMs yet, personally, although they should work. A
guy I know at work tried a Belkin USB KVM on some Sun 280R's, with mixed
results. I think it mostly worked, but there were some problems with key
mapping, like Stop-A. More information about this is required.

Good luck,
Jonathan