Thursday, February 12, 2009

PS/2 to USB adapters and KVM switches

A common call while troubleshooting KVMs is the fact that the keyboard and mouse are not working with their switch, and they can't figure out why. More often than not there are adapters the customers are trying to use and they are converting PS/2 to USB because their computer no longer has USB ports. While it seems simple enough, doing this can throw off the KVM switch and the PC. When your computer boots, if it does not see a keyboard and mouse attached it will notify you of this. A KVM switch achieves the ability to use 1 keyboard, monitor, and mouse by emulating these signals to the computer, thus allowing it to boot without any hitches. When these adapters are thrown in they are not providing that emulation, and it will appear no keyboard or mouse is attached. Other common problems in situations with no keyboard or mouse are related to PS/2 connectivity and needing a reboot, or possibly just disconnected or bad cables or even KVM hardware. As a conclusion to the thought about the emulation, there are converters that have the electronics built into them to accomplish this. If you're still having keyboard and mice trouble, check that you're not using wireless equipment unless the switch supports it. Make sure you have the correct drivers installed on all PCs. Of course there are other problems that can arise but its all hypothetical at this point.

Also a shoutout to Garrett and his site dedicated to teach people how to make MMORPG games. He put alot of time into it and it looks nice and he definitely has experience with it. Guide to Making an MMORPG

Tuesday, February 10, 2009

Reverse KVM switching


The above diagram is a scenario of needing more than 1 keyboard video and mouse on your PC. Sometimes people have a need to perform a reverse KVM switch, and split their keyboard, video, and mouse connections into more than one set of keyboard video and mice, and that is where a reverse KVM switch comes in handy. These also come in USB style reverse KVM switches and also PS/2 style. Any amount of distance can really be achieved with the most basic of reverse KVM switches, by attaching some type of Cat5 KVM extender to it and extending your KVM port that way. Alot of people wonder how 2 people can have control at the same time, but on most reverse KVM switches there are dip switches for you to set timeouts, so that User 1 would have to be idle for x amount of time before User 2 can take over. These can be very convienent if you need 2 command centers far away from the original PC. I personally think it would be advantageous to have a reverse KVM switch that ran everything over catX cable it would be alot cleaner of an install.

Friday, February 6, 2009

DDC and KVM switches and KVM extenders

When you plug in your monitor to your KVM switch or your extender, usually you expect it to work without problems and without any hangups. I have seen a growing problem while troubleshooting KVM switches, and this is very few people have an understanding of what DDC is, and many people do not know that exchanging of DDC information is usually a key factor in if your video will transmit or not with your KVM switch or extender.

Taking a step back though, DDC stands for Display Data Channel. There are VESA standards that define exactly what DDC is, but basically it is how your monitor communicates with the video card it is attached to, to notify the video card of what type of resolutions it is capable of and some other data. They store the working resolutions and the monitor and graphics card now have a common ground to display on.

The problem arises when you have a piece of hardware in the middle of the monitor and your graphics card, and this hardware does not send the DDC information to the graphics card. This will cause no video to display, or in some cases it will cause the computer to revert back to its lowest resolution. Often hard wiring the monitor and rebooting your computer takes care of this problem by letting the EDID information be exchanged, and thus having a resolution they agree on.

There are also products like a DDC ghost, which emulates DDC information, and software programs which will let you manipulate video card driver EDID information and force resolutions other than the ones in the monitors EDID information.