User & Installation manual
VHF- Communication Transceiver
Doc.-Nr:
DE-3000-800100e
KRT2
Revision 12.2
Jan. 2016
38 / 61
5.7 Electrical Connections
The 15-pin D-Sub connector contains all electrical connections except the
antenna.
The battery plus connection must be protected with at least
3-amps slow blow fuse!
5.7.1
Microphone
-
Connection
Both the L (left) and R (right) microphone input channels can either be
connected to standard microphones (standard signal level 1Vpp) or to
dynamic microphones (standard signal level 5mV to 10mV). R has less
sensitivity (30mV).
For standard microphones a supply voltage of 8V at 330Ω is provided.
Elementary Electret microphones can also be connected. They have
considerably lower signal levels and therefore require an 8V supply
voltage.
The microphone input channel amplifier gain can be selected via the MIC-
Setup menu “3.4.11 MIC – Setup”.
When dynamic microphones are used in gliders the 8V supply voltage is
switched off for power saving purposes. Also if R-input is not used it should
be loaded or grounded and not be connected to open wires.
Standard microphones normally used as in headsets, together with
dynamic microphones generally cannot be used at the same time, just
alternatively.
Motor gliders should have a toggle switch installed to differentiate between
motor less flight with dynamic microphones and powered flight with
headsets.
