User's Manual

12 Document Number: 0100SM1401 Issue: 12-16

Part C – System Topologies & Operating Modes

System Topologies

Introduction

Fundamental to understanding the use of the Q data radio range in your system is the need for a basic understanding of the

different types of radio system topologies and system topology functions.

System Topologies:

Point to Point (PTP):

• A system topology with two radios, one Entry Point and one Remote

Point to Multipoint (PTMP):

• A system topology with three or more radios, one Entry Point that directly communicates to two or more Remotes.

Point to Multipoint via a Repeater (PTMP/R):

• A system topology with three or more radios, one Entry Point that communicates via a repeater to two or more

Remotes.

Point to Multipoint via multiple Repeaters:

• A system topology with four or more radios, one Entry Point that communicates via multiple cascaded repeaters to

one or more Remotes.

Multipoint to multipoint (MPTMP):

• A system topology with one Entry Point and one or more remotes, and no repeaters, where remotes can talk directly

to the Entry Point or to each other.

• Only works with Simplex frequencies.

System Topology Functions:

Entry Point:

• The radio where user data enters the systems. Typically connected (directly or indirectly) to the Master RTU or SCADA Host.

Repeater:

• A radio which repeats data from an Entry point to Remote, or Remote to Remote, or Repeater to Repeater.

Remote:

• A radio which is the endpoint or perimeter of the system topology.

Each type of network is described in the following diagrams.

Point-to-Point (PTP)

A Point to Point (PTP) network has one Entry Point and one Remote radio. When full duplex radios are installed, full data

throughput can be achieved in each direction. Alternatively, half-duplex radios can also be implemented although collision

avoidance should be enabled.

Full Duplex radios have the advantage that they simulate a cable connection with respect to the connected devices. Even

if one device transmits continuously it will not block the other device from sending data. This is useful for applications that

expect full duplex communications or that are not designated to be radio modem friendly.