User's Manual

3-7
1N4006 diode in series with the cathode towards the audio panel in this case.
3.13 TX DATA AND RX DATA – J1 PINS 12 AND 13
These pins provide RS-232 serial communications for use with the RC-7300 remote control head if
installed. Consult the RC-7300 installation manual for details.
3.14 CHANNEL UP AND CHANNEL DOWN – J1 PINS 16 AND 17
These pins can be used to scroll up and down through the zone/channel/mode/talk group selections for the
band currently displayed on the screen. The inputs normally floating are grounded to activate. Two push
buttons or a center off, SPDT, spring loaded toggle switch are typically used on these inputs. If both pins
are grounded simultaneously, the next band will be selected.
3.15 LH DATA, SB9600 BUSY, OPTB+, CTS OUT, BOOT DIN, RTSBIN AND RS232DIN – J1 PINS 18
THROUGH 24
These pins are used for programming or updating the transceiver using Motorola Customer Programming
Software (CPS™) or encryption key loading and are left unconnected. They may be used to update the radio
once it is removed from the aircraft. These pins are also brought out to the TDFM-7300’s front panel mini-
DIN connector to allow programming in the aircraft.
3.16 PANEL BACKLIGHTING – J1 PIN 25
Connect to aircraft panel dimming bus. The transceiver is capable of supporting 28 VDC or 5 VAC
backlighting circuits. Select 28 volts DC or 5 volts AC via the configuration menu (see section 2.18). No
damage will occur if the wrong setting is made.
3.17 ANTENNA TUNER CONTROL LINES – P1 PINS 1, 2, 3, 4, 5, 6, 10 AND 12
These connections are to control an antenna tuner system such as the Foxtronics FLX-3050B. Connect
according to the manufacturer’s instructions. In the case of the FLX-3050B, the tune indicator which is
normally connected to a light, can be connected to pin 10 so that the tuning indication will show on the
TDFM-7300 display.
3.18 POWER JUMPER
The radio must be turned on manually each time the avionics bus is switched on. If it is
desired that the radio comes on with the radio master in the aircraft, remove the right
side panel from the radio and install the supplied 0.1” jumper across JP1 (two pins) near
the rear of the radio on the right side of the MCU board. The radio is shipped with the
jumper on only one of the two pins. If you attempt to turn off the radio with the jumper
installed across the two pins, it will just come back on again in 5 seconds.