WEP encryption levels (low or high) are determined by one thing: the strength/length of the WEP key used.

Most wireless devices capable of using 128bit encryption key can be dumbed down to operate in 40/64bit encryption mode.

While most wireless device manufacturers currently allow their customers to use lower (40/64bit) encryption keys, it is inevitable that over time, they will remove support for lower strength (weak) WEP encryption keys from their device drivers.

Unless you are dealing with wireless gear from different manufactures (make/model), you probably do not have to be bothered with what we are describing below.

On the other hand, if you happen to have this exiting task of making different types of wifi gear talk nice to each other, you are going to probably find the following information helpful.

If you have a mixed bag of wifi devices (64bit and 128bit WEP keys) that need to connect one access point or a common base station, you will probably have to set all of them to the lowest key strength.

Here are some facts about WEP encryption key strengths:

• 40bit WEP and 64 bit WEP: They are the same. The encryption algorithm is the same, it is just that some vendors call it 40 bit WEP, while others like to refer to this level of encryption as 64 bit WEP. Systems setup to use 40bit can interoperate with those configured as 64bit WEP, and vice versa.
  
• 128 Bit WEB: Uses a 104 bit (26 Hex character) "secret key" (entered by the user), and a 24 bit "Initialization Vector" that is internally generated.

Products/device-drivers from most leading vendors (Lucent/WaveLAN, ORiNOCO, Intersil/Harris PRISM drivers, SMC, Linksys, D-Link, etc.) can be setup to use a shared WEP key. Most of the wifi gear can be (usualy) configured to coexist with each other. Setup could get a little tricky, but it is usually because how different vendors allow you to setup various encryption parameters and their nomenclature -i.e. their screen layouts and how they label various elements on their setup screens.

Here are a few important points to remember:

• Use Correct Key Formats: Pay attention to whether a vendor allows/requires you to enter the WEP key in a specific format. Most products from Lucent, for example, allow one to enter the WEP key in either ASCII (default format) or Hexadecimal format.
  
• Prefix 0x to Designate Hex Format: If a vendor does not allow you a seperate facility to enter your WEP key in Hex format, prefix your key codes with "0x" Lucent (Wavelan) products, for example, considers a keyphrase that starts with "0x" to be a WEP key entered in Hex, and the one that does not start with "0x" prefix to be a regular (ASCII) key. This is particularly true with their older products.
  
• User Entered ASCII Key and Key Generated Using a Keyphrase: They are not the same.
  
• Use Hex Keys When In Doubt: If you are having difficulties making wifi products from different manufacturers talk to each other, try setting them all up to use Hexadecimal WEP keys. Doing so will rule out any complications due to possibly quirky key generation (from ASCII to hex) algorithms used by certain vendors.
  
• When in Doubt, Use Simple Hex Keys: Use all Zeros (0) or Ones (1) on both the client device and the APs and see if you can make them talk.
  
• When in Doubt, Use Smallest WEP Key: Set all devices to use 40 bit or 64 bit WEP key, power cycle them and see if you can make them talk.

Even though (standards compliant) wifi gear from most manufacturers should (and do ) interoperate, they often do differ in terms of how they handle environmental radio signal noise -some of them degrade gracefully, while others simply fail to establish a link. It is important, therefore, to make sure you have good signal strength before you start suspecting non-compatibility arising from their WEP implementations. It would also help to ascertain that your wifi gear has the latest firmware. If you are still having difficulties making a specific set of wifi products talk, let us know using the "contact us" link posted at the top right and we will be glad to help.