User's Manual

SEL-3031 Instruction Manual Date Code 20091009
SEL-3044 Encryption Card
Theory of Operation—SEL Protocol
B.6
Frame Replay Protection
Every frame in a given session contains a sequence number field. The value in this field
increments every time a frame is transmitted. The SEL-3044 will not accept any frame
that contains a sequence number value that is less than, or equal to, the sequence
number value received in the last frame. It is exceedingly difficult to maliciously alter
the sequence number in any given frame to bypass this functionality because the
sequence number field is protected by the strong cryptographic authentication
mechanisms. Because of the protection these mechanisms provide, an attacker cannot
capture a previously transmitted frame and resend the frame to the SEL-3044 to cause
harmful actions.
Resetting the SEL-3044
At some point it may be necessary to reset the SEL-3044. You must have access to the
front USB port on the SEL-3031. The SEL-3044 must be installed in the SEL-3031 to
reset. Use either
ACSELERATOR QuickSet
®
SEL-5030 Software or a terminal interface
to access the Radio settings. In the Radio settings, set the KEY setting to None, save
the setting, then set a new passphrase and save.
If you have lost your passwords to access the SEL-3031 then you must disable
passwords by temporarily installing a jumper. Refer to Password Jumper on page 2.10
and Ta bl e 2.5 for information and instructions on disabling passwords.
Installing SEL-3044 in the SEL-3031
The SEL-3044 can be ordered at time of purchase of the radio or it may be added later
as a field upgrade. The process involves powering down the radio, removing hardware,
installing the card, and setting the radio.
The radio contains devices sensitive to Electrostatic Discharge (ESD). When
working on the radio with the front or top cover removed, work surfaces and
personnel must be properly grounded or equipment damage may result.
!
CAUTION
Step 1. Remove the power from the radio and remove all connections from
the device.
Step 2. Rack-mount SEL-3031: Loosen the six front-panel screws and
remove the front panel.
Wall-mount model: Use a Torx
®
T15 screwdriver and remove the
four screws located on the sides of each corner. Slide the cover up and
back to reveal the front of the unit.
Step 3. Between the main board and radio board there is a PCMCIA card
slot. Gently slide the SEL-3044 straight into the card slot. Push firmly
until it is fully seated.