2.10.9
Cell Surveillance and Monitoring Threshold
The radio constantly calculates a normalized value that represents the signal strength of a cell. This
value is used by the radios to determine if the cell is usable and when to leave the cell.
In the default case, when the radio is camped on a cell, it initiates link failure procedures, such as leave
the cell, if this normalized signal strength value falls below zero. However, it is possible to configure
the radio to allow this normalized value to be processed below zero using the Customer Programming
Software (CPS); value can be set in 1 db steps up to -5 db. Reducing this value below zero allows the
radio to maintain service on a weak cell where the radio is unable to roam to a better cell.
2.11
Supplementary Services
Following is the description of the TETRA Supplementary Services (SS) that the radio supports in the
Trunked Mode Operation (TMO).
2.11.1
Transmit Inhibit Mode
The Transmit Inhibit (TXI) Mode is a mode in which the radio sends no radio transmissions. Activate
this mode in RF sensitive areas, for example hospitals, airplanes, where safety can be jeopardized due
to transmission radiation.
To activate, select
Menu
→
Networks
→
TXI Mode
→
Activate
.
In this mode, the radio does not transmit under any circumstances. All the functions and keys which
cause transmission, for example registration to the network, changing talkgroup or folder, or sending
SDS messages are disabled. Any transmission trial causes the radio to display
Not Allowed In
TXI Mode
notification and to play a tone.
Your radio can still receive and displays any incoming SDS messages. These messages are stored in
the
Inbox
.
When no danger to safety exists anymore, for example, when you leave the RF sensitive area, you can
deactivate the TXI Mode and the radio returns to standard operation.
You can deactivate the mode by selecting
Menu
→
Networks
→
TXI Mode
→
Deactivate
, or pressing
One-Touch Button.
NOTE:
RF Transmissions from the radio are prevented under the following conditions:
• TXI Mode is activated.
• Battery is removed.
• The radio is turned off.
On entering or exiting the TXI mode, when the radio is camped on a cell, it sends a specially
designated Short Data Service (SDS) status message. This SDS message indicates to the SwMI that
the radio is entering or exiting TXI mode.
Mobility procedures that do not require the radio to send an uplink transmission are performed except
for cell reselection.
If the radio is turned off in the TXI mode, on turning on, the radio asks whether to exit the TXI mode. If
you choose
No
, the radio turns off.
MN003465A01-AF
Chapter 2 : Services and Features
36
