NETGEAR CG814W Reference Manual page 131

Reference
64/128bits versus 40/104bits
You may be confused about configuring WEP encryption, especially when
using multiple wireless LAN products from different vendors. There are
two levels of WEP Encryption: 64 bits and 128 bits.
First, 64 bit WEP and 40 bit WEP are the same encryption method and can
interoperate in the wireless network. This lower level of WEP encryption
uses a 40 bit (10 Hex character) as a "secret key" (set by user), and a 24 bit
"Initialization Vector" (not under user control). This together makes 64
bits (40 + 24). Some vendors refer to this level of WEP as 40 bits and
others refer to this as 64 bits. ASUS WLAN card products use the term
64 bits when referring to this lower level of encryption.
Second, 104 bit WEP and 128 bit WEP are the same encryption method
and can interoperate in the wireless network. This higher level of WEP
encryption uses a 104 bit (26 Hex character) as a "secret key" (set by user),
and a 24 bit "Initialization Vector" (not under user control). This together
makes 128 bits (104 + 24). Some vendors refer to this level of WEP as 104
bits and others refer to this as 128 bits. ASUS WLAN card products use
the term 128 bits when referring to this higher level of encryption.
21 ASUS WLAN mini-PCI card