LevelOne WCS-2000 - Manual (Page 29)

The other key values are optional, and are used only for decrypting
data. This allows you to use different keys for transmitting and
receiving, if required.
When inputting a key value, follow these rules:
• For 64 Bit Encryption, keys must be 10 characters.
• For 128 Bit Encryption, keys must be 26 characters.
• Keys must be entered in Hex.
Hex characters are A ~ F, and 0 ~ 9.
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