- The number of Ports (computers) the switch supports
- On Screen Display (OSD)
- Operating Systems Supported
- Peripherals Supported
- Type of Monitors Supported
- Number of Monitors Supported
- Number of Users Supported
- Form Factor
- Type of Cabling
- Type of Technology
The number of computers that a KVM Switch supports will greatly affect the price point. Obviously a 2-Port KVM will be less expensive than a 16-Port KVM since there is a lot more that has to go into the manufacturing of the higher port switch.
2. On Screen Display (OSD)
Some of the KVM's that we carry offer On Screen Display (OSD) that allows you to graphically navigate your way through the KVM. If you only have a 2-Port Switch you probably do not need OSD to effectively manage your computers. If you have an enterprise KVM such as the Avocent AMX5000 and you are controlling hundreds to thousands of servers than you definitely will need an OSD to find the computer that you need to access. There are different types of OSD's created by each manufacturer and there is no standard for them. In the majority of the OSD's you are able to name each connected computer for easy reference.
On the smaller scale IOGEAR created a 2-Port and 4-Port
USB KVM Switch that allows you to share USB peripherals between the computers. In the OSD of these switches you can select which computer you want to control as well as where you want all the shared peripherals to be connected. This is a good option so you can continue scanning or printing on one computer while you check email on another. In original USB KVM's that allowed peripheral sharing if you switched to another computer while using a peripheral it would lose the connection and the job would fail.
While the On Screen Display is a great addition to any KVM setup it is an added cost and therefore that should be kept in mind when looking at these switches.
3. Operating Systems Supported
There are many different types of operating systems available such as Microsoft Windows 95/98/98SE/NT/ME/2000/XP, Mac OS, Linux, Unix, and Sun Solaris. Creating a switch that has the added compatibility with all these different operating systems is more expensive since they have to add all the converters into the switch itself. This is a great feature if you are using different types of computers so you don't have to have external converters therefore adding more clutter to your work area. For larger server room installations this will probably be a necessity as it is very likely that you will have a variety of different components you will need to control. Some switches will also allow you to control Serial devices such as routers and hubs from the same device you control your servers with. You will need to check the specifications of the switch before you buy it to make sure that it supports that operating system that you have.
4. Peripherals Supported
Through the evolution of computers different types of peripherals have been created to control your computer. For PC's it started with a Serial/AT keyboard and mouse combo that led into PS/2 and now the general direction is towards USB. For Sun it started with MiniDin-8 and they have moved towards USB as a standard now. Mac's started with their ADB connection then moved to USB. It seems that most manufacturers are moving primarily towards USB since it adds a great deal of functionality to the Keyboard and Mouse to make your experience much better but it is doubtful that there will ever be a universal standard for peripherals. With this in mind some switches will support multiple connections within the same box.
There are switches that only support a certain set of peripherals with the most common being PS/2 and VGA. There are also switches that support only USB/VGA, USB/DVI, and PS2/DVI. These switches are less expensive the multi-platform switches since there is less intelligence built in.
A great solution for 4 computers or less in the Avocent SwitchView 1000 4 Port as it will handle PC's (PS2/USB/AT with VGA), Mac's (USB w/VGA), Linux (PS/2 and USB w/VGA), and Sun (MiniDin-8/13W3, MiniDin-8/VGA, or USB/VGA) all without any additional converters.
In the middle of the spectrum for computers numbering from 8-24 there is the Avocent AutoView family.
On the largest scale the two industry leaders are the Raritan Paragon II and the Avocent AMX5000.
5. Type of Monitors Supported
Originally each computer manufacturer supported their own monitor type. PC's had VGA, Mac's had ADB, Sun's had 13W3, and so on. Now there is a little crossover but there are still proprietary monitors as well. VGA is still the most dominant but there is a lot of growth in the DVI field as the digital picture is superior to Analog. Macintosh has created the Apple Display Connector (ADC) that allows Video, USB and Power to be sent through the same cable. This is a great feature but it is only available on the newest Mac's and support of it in KVM's is expected to be minimal.
Since DVI is relatively new the amount of support for it in KVM's is very small but there should be more wide-spread support available for it in the near future. There are a handful of DVI KVM switches available that support either USB or PS/2 peripherals
KVM's that support only VGA monitors will be the least expensive since they are the most common. When you start looking at switches that support a different type or multiple types the price will rise accordingly with ADC and DVI being the most expensive.
6. Number of Monitors Supported
The majority of computer setups use only a single monitor per computer but there is a growing number of setups that use multiple monitors. This is really handy for people that have multiple applications open at a single time and people that do a lot with graphics. There are KVM's that handle multiple video card setups and some can support multiple video types as well as multiple peripheral types. The highest quality and most versatile of the group is the Rose MultiVideo allowing up to 4 computers with up to 4 monitors on each computer. The others are Dual monitor KVM and support 2 or 4 computers with 2 monitors.
Since this is also an added feature and not very common the price will be higher than single monitor KVM's.
7. Number of Users Supported
Some KVM's will offer support to allow multiple users to access all the computers connected to the KVM Switch. This is more applicable in Server Room or Data Center setups but could be used in work bench type scenarios as well. The amount of users varies from 1-64 but the numbers can go beyond that as well. Of course the more users you need to support the more the price will go up.
8. Form Factor
The form factor of KVM Switches vary greatly from coming with attached cables such as the IOGEAR GCS62, to sitting on top of the desk like the Avocent SwitchView, to sitting along side your monitor such as the Belkin Flip KVM. Of these different styles the most expensive is generally the rack mountable since they require mounting brackets and have to have structural modifications to support their own weight and cabling. The type of casing also affects the price with metal being more expensive than plastic.
9. Type of Cabling
There are different types of cabling and this can affect the cost of the switch but most likely it will affect the price of the cables themselves. The most common is a standard KVM Cable. This consists of three cables (or two with USB) being bonded together containing the keyboard, monitor, and mouse cable connections on either end. Some manufacturers use proprietary cabling so you must use their cables with their switch therefore raising the price of the cables. This is more common in Multiplatform switches than PS/2.
Some switches utilize Cat5 cable from the switch to the computer to make the cabling more simplified and easier to run. The cost of the Cat5 is very low but you must purchase the correct dongle for the computer and these are more expensive then standard cables. This setup is only utilized in larger setups and not for home scenarios. With Cat5 the distance limitations are also lengthened since the signal is converted and sent rather than just using a regular cable.
10. Type of Technology
There are two major types of technology being deployed today; Analog and Digital. For the majority of scenarios the Analog switch will make the most sense. Analog KVM's are anything where you are physically connected to the KVM and computer via a cable. Digital switches are ones that work over the LAN or WAN using software or an internet browser such as Microsoft's Internet Explorer. Digital KVM's are generally only deployed in large Server Room or Data Center's where running a lot of cables causes problems or when people need to be able to access their servers across campus, the country or even the world. This type of technology is called KVM Over IP and there are many different models you can choose from with different features. If you want the ability to access your servers from anywhere there is a premium on the technology.