Codan NGT 2010 RF Technical & Service Manual page 644

NRI—Overview and specifications
RF unit
The RF unit modulates audio signals onto radio frequencies that can be transmitted on
air, and demodulates the radio frequencies it receives into audio signals.
NGT remote interface
The NRI provides a method of extending NGT CIB via an RS232 serial data link by
converting CIB audio, control and status signals to and from RS232 data. For correct
operation of the NRI, the RS232 link requires a minimum line speed of 9600 bps in full
duplex mode. The RS232 introduces additional system delays for both audio and control
signals. In conjunction with a line modem, the RS232 link is achieved across a 2-wire
telephone line.
Switchmode power supply
The switchmode power supply is used to supply power to the NRI at the control site.
This unit converts mains power supplies ranging from 90–260 V AC to a regulated
13.5 V DC supply, which is suitable to power the NRI and line modem.
Line modem
Refer to the documentation provided with the line modem. The line modems provide the
RS232 link between the control and transceiver sites via a 2-wire telephone line.
Transceiver supply
A PSU, such as a 3020 Transceiver Supply, is used at the transceiver site to provide
power to the transceiver, NRI and modem.
Antenna
The antenna receives and transmits the radio signal. For a detailed description of the
types of fixed antenna available see the NGT Transceiver Reference Manual provided
with your transceiver, or the Antenna Matrix.
Remote control junction box
A remote control junction box is used to provide an RS232 serial data connection
between the control site and the HF data modem at the transceiver site.
HF data modem
The HF data modem provides an interface that enables data to be sent or received. Refer
to the documentation provided with the HF data modem.
NGT Transceiver System Technical Service Manual 251