Tyco Electronics M/A-COM MM23016 - Manual (Page 40)

MM23016, Rev. C
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• If scan mode is set to “Normal” and the emergency was declared on the selected talk group, the
selected/emergency talk group’s name remains in the top line of the display. Audio on the emergency
talk group is heard in the speaker/headset.
• If scan mode is set to “Normal” and the emergency was declared on a talk group other than the
selected talk group, the emergency talk group’s name appears in the bottom line of the display. Audio
on the emergency talk group is heard in the speaker/headset.
• The declaring radio's alias appears in the bottom line of the display when the emergency talk group is
selected.
• An emergency call can be dismissed as described in the following section.
A radio declaring an emergency on a talk group has a “hot” mic time period of typically
ten (10) seconds just after it declares the emergency. This time period may be adjusted
by system or network administration personnel on a per radio basis.
7.29.5 Dismissing an Emergency Call
An emergency is dismissed for a configurable amount of time only (default = 5 minutes).
To ignore an emergency call declared by another radio user:
1. Press until “EmgDismiss” appears in the display.
2. Press until the talk group in the emergency state appears, as indicated by an asterisk (*)
following the talk group’s name.
3. Press the MENU button.
The emergency dismiss timer is cleared when the emergency is cleared.
7.30 ENCRYPTION
In the OpenSky network, both data and voice use a 128-bit or 256-bit key encryption standard published
by the Federal Information Processing Service (FIPS), called Advanced Encryption Standard (AES). AES
is approved by the U.S. Department of Commerce for encryption of classified materials.
When encryption is enabled on the network, data is encrypted from the MDIS to the Mobile End System
(MES) (e.g., M7200 mobile radio). This form of encryption provides air-link security.
Voice encryption is handled either automatically or manually. Automatic encryption is initiated through
the Unified Administration Server (UAS) for a specific talk group and requires nothing from the user.
Manual encryption is initiated by two or more radio users and requires system model control heads. Both
methods of encryption are discussed in the following sections.
7.30.1 Automatic Encryption
For automatic encryption, a network administrator will select the talk group to be encrypted at the
interface to the UAS. Once the talk groups have been selected and identified as secure, credentials for key