F E A T U R E G U I D E
password parametrized, the time value can be anything between 1-160, the value 0 sends NMEA to TE until power
off.
Time recovery
If the radio has been out of main power and has consumed all the power stored in the backup batteries, the in-
device main clock resets. At the next startup the condition is recognised and the TDM880i starts to recover the clock
state. During the recovery process, the following steps are taken:
1. The device tries to connect into the network and receives the current network time.
2. If the network does not provide the main time within 10 minutes, the network recovery is continued and the device
tries to recover the time from the GPS signal.
Recovery from power failure
The TDM880i is powered by an external DC supply (10.6 - 16 V).
Starting up the TDM880i after an external power supply failure requires that at least one of the three IGS signals is
held in the logic high state. If all the IGS signals are kept in the logic low state after a power supply failure, the device
does not start up.
When an external DC supply is applied, or if you want to start up the TDM880i automatically after a power failure,
you should permanently connect the IGS signal in the connector X104 (pin #5) to the power supply pins #1, #2 and
#3 of the same connector (that is to the main DC supply pins/wires). In that case, you must shut down the device by
disconnecting the external power supply.
If the device has lost main power and runs out of backup power, the main clock of the device resets. In this case the
Time Recovery sequence is started during the next startup. See Section Time recovery on page 19.
When the device has no power, the I/O lines are in an undefined state. Use external pull-up and pull-down resistors
in the I/O lines if the I/O should have a defined state in power off. Note also that the Power On indicator, In Service,
and Over-temperature indication signals are driven high but are in high-Z when not driven. These signals should not
have an external pull-up resistor in order to get a valid result (there is a weak pull-down in each signal line). An
external pull-down resistor is recommended to be used in these signals. After recovering from a power failure, the I/
O lines are driven to the state they were in before the power failure. The only pins that do not behave this way are
the GPS fix and In Service indication pins. These I/O pins indicate the real status of the GPS or TETRA service
availability.
Temperature protection
The device monitors its internal temperature and shuts down the transmitter in the event of overheating. An
overheating indication will be sent over an AT command interface (and indicated by I/O line).
After a sufficient drop in internal temperature, the device returns the transmitter to normal operation, and indicates
this event to an external application by the I/O line and by AT indication.
Note:
During the period of direct routing, the AT channel is not available.
Note:
After the NMEA redirect period ends, the GPS is disabled.
Note:
At any time during the recovery, the end user is able to set the time using the AT interface, but if the
network recovery is activated, it supersedes other recovery functions.
Note:
The TDM880i utilizes UTC time (Coordinated Universal Time).
Содержание TDM880i
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