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CHAPTER 2
Communications System Design
Designing an IP-223 system requires an understanding of the radio network and how the various radios and communication
equipment are connected.
Design an IP-223 system by creating a roadmap of the radio, console, and any other communication equipment locations. This
roadmap must include the following:
• Multicast addresses for each channel of TX (transmit) and RX (receive) communication.
• Port numbers for each channel of TX and RX communication.
• Base IP Addresses assigned to each console and IP-223 on the network.
Communications Control
Tone Remote Control
Telex sells a full line of tone control consoles and radio adaptors. This technology requires an analog connection between
console and radio. Each console needing to control an individual radio is wired in parallel to allow multiple operator positions
to monitor and control the same radio. For a large system with multiple console positions and multiple radio channels, an
entire rack might be devoted to bridging audio to all interested parties. In addition, due to loading of multiple consoles on a
particular circuit, additional bridging hardware might be required, increasing wiring and tuning of the system for acceptable
performance. The Ethernet-based IP network solves many of these issues and provides for a number of other services not
previously possible.
VoIP Radio Control
RoIP (Radio Over Internet Protocol) being a subset of VoIP is referred to as VoIP generically throughout this document. VoIP
is a method of breaking analog audio up into packets that can be transferred over a computer data network. Because of the
Ethernet delivers information packets, audio is generally broken into 10-40ms chunks of audio, compressed, and placed on the
Ethernet. The nodes of the network are then free to utilize or ignore any combination of packets. If a particular audio stream is
of interest, the stream of audio packets are captured, encompassed, converted back to analog, and played on available
speakers.
Given the popularity of the Ethernet-based networks, many companies and agencies already have an existing network or LAN
(Local Area Network). Beyond that, a large number of companies exist to provide WAN (Wide Area Network) connections
between sites with significant distances between them. The WAN connections can be used to connect offices across the street
from one another, around the world, or anywhere in between. Possibly the best thing about these connections is they may
already exist. In many cases, WAN links are less expensive than a comparable leased analog line and they can carry more
conversations simultaneously.
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