HomeMy WebLinkAboutSystem Reliability FeaturesSystem Reliability Features
Transmitter Power Shutdown
1. DESCRIPTION
The MTC 3600 can detect a loss or decrease in
transmitter output power of all trunked repeaters
connected to it. Each trunked repeater contains an
internal wattmeter element. Once the forward power
has decreased past the threshold set, the repeater
instructs the central to take the channel out of service.
If reflected power increases past the threshold set, the
repeater will also instruct the MTC 3600 to take the
channel out of service. This information is conveyed
via the RS232 cable connection between the MTC
3600 and the trunked repeater.
VERSION #1.09
City of Miami, Florida
Mobile Communications System
IFB No. 28069 - Appendices
July 5, 2007
2-36
2. TEST
Step 1.
Disconnect the transmit antenna connection
to trunked repeater 1. This will cause a high
VSWR condition.
Step 2. Key RADIO-1 so that channel 1 is assigned,
and verify that the MTC 3600 will fail this
channel. The interface for channel 1 on the
ACE card will show the orange disabled
LED driven.
Step 3. Restore the transmit antenna connection to
trunked repeater 1. Verify that the channel is
put back into service by the MTC 3600
within five minutes.
Pass Fail
Motorola Confidential Restricted
Use or disclosure of this proposal is
subject to the restrictions on the title page
Receiver Interference Shutdown
1. DESCRIPTION
An unauthorized signal is received by a trunked
repeater. The interference does not contain the sub -
audible connect tone that the central controller is
looking for. This can be caused when a mobile from
another system with similar frequencies strays into
trunking system range. In order to prevent a
disruption of communications, the MTC 3600 will
remove this channel from trunked system selection or
assignment process when it detects an illegal carrier
for longer than the specified time out period. Once
the interfering carrier ceases, the channel is returned
to service.
The time-out period (Carrier Malfunction) which is
set by the PARM command in the MTC 3600 via the
System Manager Terminal, may be set to 1 to 253.
Setting the value to 254 will disable the Receiver
Interference Shutdown feature.
VERSION #1.06
Motorola Confidential Restricted
Use or disclosure of this proposal is
subject to the restrictions on the title page
2. TEST
Step 1. Using a service monitor, generate a 1 kHz
tone on the receive frequency of trunked
repeater 1, modulate the signal at 3.0 kHz,
with no connect tone.
Step 2. Access the PARM command via the SMT
terminal.
Step 3.
Step 4.
Set the Carrier Malfunction Time Out
Parameter to 10 seconds with MA
command.
Verify that within 10 seconds the MTC 3600
will fail the trunked channel. The shutdown
can be monitored on the front panel of the
MTC 3600. The interface for channel 1 on
the ACE card will show the orange disabled
LED driven. The Channel Status routine of
the SMT will also confirm that the channel
is disabled. The SMT will also generate an
error message indicating this failure.
Step 5. Remove the interfering signal, and verify
that the controller will put this channel back
into service within five minutes.
Pass Fail
City of Miami, Florida
Mobile Communications System
IFB No. 28069 — Appendices
July 5, 2007
2-37
Failsoft Operation
1. DESCRIPTION
To ensure continued communications, the trunked
system will enter "failsoft mode" in the event that the
MTC 3600 can no longer control the trunking system.
Failsoft operation will occur if any of the following
conditions are present:
- No Control Channels available
- No Voice Channels available
- Loss of any MTC 3600 site
- Loss of any main MTC 3600 boards
- Loss of power to MTC 3600
When in this mode, trunked radios operate as they
would on a conventional repeater system. In failsoft,
talkgroups are distributed across the different trunked
repeater channels. These assignments are part of the
customer fleetmap plan and are preprogrammed into
each trunked radio, as well as consoles operators.
Since there are a limited number of trunked channel
resources, different talkgroups will share the same
failsoft channel. These talkgroups will be merged
together for the duration of failsoft. It is important to
ensure that the groups that normally communicate
together while the system is trunking should fail to
the same trunked repeater in failsoft.
Trunked radio users are alerted to the failsoft
condition by visual display of failsoft, and a periodic
audible tone.
VERSION #1.03
City of Miami, Florida
Mobile Communications System
IFS No. 28069 — Appendices
July 5, 2007
2-38
2. TEST
Step 1. Disable all possible control channels via the
SMT.
Step 2. Verify system enters failsoft and all trunked
repeaters immediately key up.
Step 3. Verify that RADIO -I and RADIO-2 enter
failsoft mode, and hear periodic failsoft
tone.
Step 4. Verify communication per the entire
fleetmapping plan toensure proper
operation.
Step 5. Enable the control channels.
Step 6. Verify that the system resumes trunking
within 5 minutes
Pass Fail
Motorola Confidential Restricted
Use or disclosure of this proposal is
subject to the restrictions on the title page
Control Channel Rotation
1. DESCRIPTION
In the event that the assigned control channel fails,
the MTC 3600 automatically selects one of the other
eligible channels as the active control channel.
Assignment of the control channel falls into two
categories: assignment when the system comes into
trunking operation and reassignment after a control
channel failure.
VERSION #1.03
Motorola Confidential Restricted
Use or disclosure of this proposal is
subject to the restrictions on the title page
2. TEST
Step 1. Verify that there is an active control channel
is channel.
Step 2. Front panel disable the active control
channel.
Step 3. Verify that the control channel has rotated to
the next available channel and is processing
calls.
Step 4. Disable the control channel via the SMT
CHAN command.
Step 5. Verify that the control channel has rotated to
the next available channel and is processing
calls.
Step 6. Re -enable the channels.
Pass Fail
City of Miami, Florida
Mobile Communications System
IFB No. 28069 — Appendices
July 5, 2007
2-39
Base Station Identification
1. DESCRIPTION
The system call sign is automatically transmitted via
International Morse Code once every 30 minutes in
compliance with FCC regulations. This message is
sent in Morse code at 17 words per minute using 900
Hz tone modulation.
VERSION #1.01
City of Miami, Florida
Mobile Communications System
IFB No. 28069 — Appendices
July 5, 2007
2. TEST
Step 1. Set up a service monitorto monitor the
lowest available transmit frequency in the
system.
Step 2. Within 30 minutes, a series of 900 Hz tones
are heard.
Pass Fail
Motorola Confidential Restricted
Use or disclosure of this proposal is
subject to the restrictions on the title page
2-40
Station Failure
1. DESCRIPTION
When a Base/Repeater Station fails due to hardware
problems, the system will not assign that repeater.
VERSION #1.06
Motorola Confidential Restricted
Use or disclosure of this proposal is
subject to the restrictions on the title page
2. TENT
Step 1. Access disable the base station/repeater for
one channel.
Step 2. Press PTT on RADIO-1 several times until
failed station is assigned.
Step 3. Notice the MTC 3600 marks the channel as
failed,
Step 4. Press PTT on a radio several times to utilize
all available voice channels.
Step 5. Verify that the disabled repeater channel is
not used.
Pass Fail
City of Miami, Florida
Mobile Communications System
IFB No. 28069 — Appendices
July 5, 2007
2-41