Codan NGT 2010 RF Technical & Service Manual page 643

NRI—Overview and specifications
Overview
The remote control NGT system can be used with NGT AR, SR and ASR Transceivers. It
enables you to install your transceiver in a remote location and control it from another
site. For example, you can install your RF unit and antenna at a site that benefits from
low-level noise interference for improved reception, while controlling it with the handset
from a convenient control point, such as an office.
The audio and control connection between the sites is achieved by using the latest in
digital voice technology. The digital voice and control data signals are combined into a
single RS232 data connection with a minimum line speed of 9600 bps in full duplex
mode.
This document assumes that the RS232 data connection is achieved over a leased land
line using two industrial-quality line modems. The maximum combined cable length
between each site and the exchange is 19 km.
The basic layout of the remote control NGT system is shown in
Figure 1: Basic layout of the remote control NGT system
Desk
NRI
console
Switchmode
power
supply
Components in a remote control NGT system
Handset
The handset is a hand-held device that has a microphone, PTT button, display and
keypad. The microphone and PTT button are used for voice communication. The keypad
enables you to control and configure the transceiver system. The handset is connected to
the junction box.
Junction box
In a remote control NGT system, the junction box is the unit to which the handset, NRI,
speaker and related units may be connected. It interprets the instructions you enter
through the handset then sends them to the appropriate units in the system. Extra
junction boxes, called remote control junction boxes (see
junction
250
Line
modem
box), are used to connect data modems into the system.
Line
NRI
modem
page 251, Remote control
NGT Transceiver System Technical Service Manual
Figure 1.
RF unit
Codan
transceiver
supply