CL4490 User Guide
Version 3.0
Americas: +1-800-492-2320 Option 2
Europe: +44-1628-858-940
Hong Kong: +852-2923-0610
www.lairdtech.com/ramp
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Laird Technologies
CL4490 Security Features
In addition to FHSS technology, Laird has implemented three levels of security in the CL4490. All three levels
associate with their own EEPROM parameter that you may program for permanent operation or change
during system operation in volatile memory using on-the-fly commands (download the
for more information). The first two levels of security must configure and establish a
network of transceivers and are defined as the RF Channel Number and System ID.
The RF Channel Number represents a specific hopping sequence and provides physical separation between
collocated networks. Thus, all transceivers in a network must use the same RF Channel Number. There are a
total of 56 Channel Numbers.
Note: RF Channels 0-47 are restricted to US/Canada, RF Channels 48-55 restrict operation to 915-928
MHz and are normally only used in Australia.
System ID is similar to a password character or network number and makes network eavesdropping more
difficult. A receiving radio will not go in range of or communicate with another radio on a different System
ID. There are a total of 256 System ID values.
If FHSS technology, Channel Number and System ID are still not enough to secure your data, the CL4490 also
supports the Data Encryption Standard (DES), which is the third level of security. Encryption is the process of
encoding an information bit stream to secure the data content. The algorithm described in this standard
specifies both encrypting and decrypting operations which are based on a binary number called a key.
A key of 56 bits is used encrypts and decrypts the data. The encryption algorithm specified in this standard is
commonly known among those using the standard. The unique key chosen for a particular application makes
the results of encrypting data using the algorithm unique. Selection of a different key causes the encrypted
data that is produced for any given set of inputs to differ. The cryptographic security of the data depends on
the security provided for the key used to encrypt and decrypt the data.
Recover data from the encryption by using exactly the same key used to encrypt it. Unauthorized recipients of
the encrypted data who know the algorithm but do not have the correct key cannot derive the original data
algorithmically. However, anyone who does have the key and algorithm can easily decrypt the encrypted data
and obtain the original data. A standard algorithm based on a secure key thus provides a basis for
exchanging encrypted data by issuing the encryption key to those authorized to have the data.
