MAINTENANCE GUIDE | MT-4E ANALOG & P25 DIGITAL RADIO SYSTEMS
Chapter 5: Codan Radio System Testing
Page 20
Turning OFF the MT-4E Receiver and Transmitter Modules
Turning the switch on the front panel of the MT-4E receiver or transmitter modules to the OFF position
can cause unwanted eff ects on other MT-4E receiver and transmitter modules.
When the MT-4E receiver and transmitter are connected directly together with the LVDS serial data
RJ45 cable, turning the MT-4E transmitter front panel switch to the OFF position will cause the MT-4E
receiver module to turn off . The MT-4E receiver modules A and D LEDs on the front panel will blink on
and off when this occurs. Turning the MT-4E receiver modules front panel switch to the OFF position
will not cause any adverse eff ects on the MT-4E transmitter. When turning the MT-4E receiver modules
front panel switch from the OFF to NORM position (or vice versa), it will cause the MT-4E transmitter
to reboot. Remove the RJ45 cable to stop this interaction from occurring. When connecting the LVDS
serial data RJ45 cables to the CI-RC-4L repeater control card or CI-RC-4M-G2 multiple link controller,
the MT-4E receiver and transmitter modules are isolated from each other and the modules can be
turned on or off independently of each other.
When the MT-4E receiver and transmitter channel and bank select lines are connected together in
parallel, turning the MT-4E receiver or transmitter front panel switch to the OFF position will cause the
channel and bank select lines to be grounded. This will cause the other MT-4E module to operate on
Bank B, Channel 1 regardless of how the channel and bank select lines are set. If the bank select lines
are not connected in parallel, only the channel will be aff ected. The channel select lines are independent
of the LVDS serial data RJ45 cables (the cables will have no impact on the channel select).
When the MT-4E receiver and transmitter are connected to the antenna relay in the System Regulator
module, turning the MT-4E transmitter front panel switch to the OFF position will cause the MT-4E
transmitter PTT OUT line to be grounded, activating the antenna relay and causing it to be switched so
that the transmitter is connected to the antenna. This makes it impossible to test the MT-4E receiver
through the antenna relay when the MT-4E transmitter is turned off .
When performing maintenance on the Codan MT-4E radio system it is best to simply remove the MT-4E
receiver or transmitter, that is not being tested, from the subrack and disconnect all RJ45 cables, rather
than turning the front panel switch to the OFF position. All Codan modules are hot swappable. There is
no need to disconnect the power supply when inserting or removing the modules from the subrack.
Summary of Contents for MT-4E
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