the KVM network

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introduction

KVM (Keyboard, Video, Mouse) is the interface between a person and an IBM PC. This set of three pieces of hardware is attached to one base unit.

All the LIC PCs are connected to three old 8 port KVM switches with PS/2 sockets.

what it is

The LIC contains many computers. I can't buy lots of KVM sets, one set for each base unit. That would take up far too much room in my shed. I can use a KVM switch to share one KVM set between many computers.

LIC topography: KVM (Keyboard, Video, Mouse) things
8 port KVM switch and cables CRT video monitor keyboards and mice

Each of my old PCs has a VGA connector (a 15-pin D-sub socket) for the video monitor, a PS/2 connector for mouse and another /2 connector for the keyboard. A KVM switch is advertised as having several ports: these three connectors are together called a port. One KVM cable, which connects one PC to one port, is three cables stuck together.

I need to be able to plug in eight PCs (6 PCs inside the LIC and 2 outside). I didn't buy one 8 port KVM switch: I bought three. And another 2 port KVM switch. Why buy 26 ports when I need 8? Well, two reasons.

  • I have lots of spare KVM switch ports so in future I can expand the LIC with more computers.
  • Each KVM switch is plugged into a different part of the power network, so if a fuse blows and the power fails to one KVM switch I can still use others. This is part of the HA architecture.

This does mean I have no less than four keyboards and mice on my desk. I plugged in two black keyboards and two white ones to lessen my confusion about which one I am supposed to be typing on.

In these flat panel days of LCD (Liquid Crystal Display) monitors, big old CRT (Cathode Ray Tube) monitors are dirt cheap. They are bulky, heavy and no longer desired by the masses. Fantastic! The quality of a lot of these old monitors is better than their LCD equivalent.

rack placement

LIC topography: KVM
                                                 
                                                 
                                                 
                                    cks01   cvm01        
                                                 
                                                 
                                    cks02   cvm02        
                                                 
                                                 
                                    cks03   cvm03        
                                                 
                                                 
                                                 

I put one 8 port KVM switch on each shelf of the rack. I also had another smaller KVM on top of the rack, for the PCs that are not in the LIC.

One 8 port KVM switch named cks01 sits on shelf "01" of the rack. The video monitor cvm01 sits here too. the keyboard ckb01 and mouse cms01 are on my desk. All LIC computer names ending in"01" are plugged in here, like ifw01 and ics01.

One 8 port KVM switch named cks02 sits on shelf "02" of the rack. The monitor cvm02 sits here too. Keyboard ckb02 and mouse cms02 are on my desk. All LIC computer names ending in"02" are plugged in here, like ifw02 and ics02.

One 8 port KVM switch cks03 and monitor cvm03 sit on shelf "03". Keyboard ckb03 and mouse cms03 are on my desk. PCs ifw03 and ics03 are plugged in here.