User's Manual

Table Of Contents
TDFM-136B Operating Instructions 08RE399
2.5 Encrypted Operation
The TDFM-136 supports encrypted operation using both DES OFB and AES encryption
keys for P25 communications. The sequence to use encryption is as follows:
1. Load keys using a KVL keyloader.
2. Assign a KeyTag (name) to a key, defined by its SLN.
3. Assign a key, via the KeyTag to a memory.
4. Enable or disable use of encryption in radio operation.
2.5.1 Loading Encryption Keys
In order to use the encryption feature on the transceiver, you must have encryption keys loaded
into the unit. The keys must be loaded into the unit using a KVL-3000+ keyloader. Of course the
keys must have been created in the KVL first. Operating instructions for the KVL are beyond the
scope of this document, see manufacturer documentation.
Note: The keyloader (KVL) must be connected to the transceiver with the correct cable: ensure
you only use a cable designed for use with the TDFM-136B.
Once you have a KVL with the correct keys loaded, follow this procedure to load and use them in
the transceiver:
1. Connect the KVL to the TDFM-136 via the correct cable.
2. Load the keys following the KVL procedure. The keys will load to the Main or Guard
module as determined by the front panel switches.
3. Once you have loaded one module, you must load the same keys in the same order into
the other module. This is because the Guard operation is split across the two hardware
modules.
2.5.2 Assign KeyTag to Encryption Keys
Once the keys have been loaded, you need to assign a name (referred to here as a KeyTag) to the
key so that they can be manipulated later. Initially, the key will be identified by it's SLN (sometimes
called CKR).
Command L4-8 allows you to set the KeyTag for any of the keys loaded into the radio following this
sequence:
1. Select the key, by SLN, to assign a KeyTag to.
2. Enter the KeyTag
3. Repeat for other SLN's if desired.
Select Key by SLN. The first screen, shown below, allows you to step through the available
keys (by SLN), and shows the encryption algorithm for that key.
Figure 2- 25 . The screen to select the SLN to assign the KeyTag to.
Technisonic Industries Ltd. 23
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