MITSUBISHI ELECTRONICS AMERICA, INC.
ST200 Series Technical Support Manual
23
January 2000
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System Deactivation
♦
Low Power
♦
Temperature Alarms
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Loose or Disconnected Cables
System deactivation is when the CGS commands the MT to deactivate (handset display:
Shut
Down
) due to network congestion, MT failure of a performance verification test, detection of
corrupt NVRAM, or the need for excessive re-transmissions to successfully deliver messages. It
is also possible that the Aeronautical Mobile Satellite Service (AMSS) may exercise its priority
access rights in emergency situations. In these cases the dealer must coordinate with the MSAT
service provider to request reactivation. This situation may also require re-commissioning.
An MT may automatically shut itself down if it detects low power or high temperatures. In both
cases the MT notifies the user of the situation with an audible warning tone prior to automatic
shutdown. In most cases the user can terminate a call in progress before automatic shutdown.
Finally, an MT may power down or not be able to power on if there are loose or disconnected
cables. Proper MT operation requires secure connections between the handset, CTU, and AU.
Damage to cables may also cause the power-off condition.
5.8 Operation
5.8.1 Initialization
The Mitsubishi MTs run through a hardware and software self-test procedure every time a user
applies power. The MT will request programming information the first time that it powers up.
After programming, described in Section 7, the unit will automatically power down. When the
user powers up again, the MT will request the Pilot Frequency Code (PFC) and the
Commissioning Frequency Code (CFC), which the dealer obtains from the MSAT service
provider. These codes identify the pilot channel frequency (for satellite location) GC-S channel
frequency (for commissioning messages). The land mobile MTs can now find the satellite and
begin commissioning. Fixed site and transportable MTs require manual antenna pointing
towards the satellite. This setup procedure is described in the following section (5.8.2).
The commissioning procedure automatically starts after the user responds to the
push SEND
button prompt from the MT. The initialization request from the MT goes over a special MET-
SR channel to the CGS. The CGS then verifies that the MT is registered and sends a response,
including initial assignment and identification information. The CGS then commands the MT to
perform a Performance Verification Test (PVT) including both the signaling and the
communications channels. For communications channel testing, the MT enters a
loopback
mode, sending data to the NCC for checking errors. After the MT successfully completes the
PVT, the NCC sends a commissioned indication to the MT, indicating that it is ready for service.
