Psion Teklogix 9160 G2, User Manual, Page: 245 / 436

Chapter 22: The 9160 G2 As Base Station
Overview
Psion Teklogix 9160 G2 Wireless Gateway User Manual 221
22.1 Overview
The 9160 G2 Wireless Gateway can function as either a wired or wireless Base Station, or as
a Remote Radio Module (RRM), using a radio link and Psion Teklogix proprietary protocols
to facilitate communications with the mobile computers (see “Radio Protocols” on page 222).
As a wired base station, the 9160 G2 can communicate with wireless mobile computers
using Adaptive Polling/Contention Protocol (page 222), and is connected to the network
controller over a network.
As a wireless base station, the 9160 G2 communicates with the wired base station and
mobile computers using 802.11 WDS.
As an RRM, the operation and timing of the 9160 G2’s radio link to the mobile computers is
directly controlled by a network controller that uses a timeplexing radio protocol (see
“Timeplexing And Cellular Switching”, below). It is connected to the network controller
over a network.
Timeplexing And Cellular Switching
There are two methods of operating on the radio link. The first method is called cellular
switching . It is similar in concept to cellular telephone systems. Here, each base station uses
a different radio channel. The mobile computers monitor the radio link and automatically
switch to the channel with best radio reception. This cellular switching capability is trans-
parent to the host.
The second method is called
timeplexing . Here, all Remote Radio Module (RRM) bases at
the site use the same channel. Over a UDP/IP network, a network controller coordinates the
polling sequence so that the RRMs do not transmit simultaneously. This timeplexing capa-
bility is also transparent to the host. Timeplexing is suited for sites with low transaction
rates.
Cellular switching and timeplexing can be combined within one Psion Teklogix system: a
site may operate on two or more channels, with several grouped timeplexed bases using
each channel, and cellular switching between the channels.
In all of these cases, the operator may move freely throughout the site without loss of com-
munication. The Psion Teklogix system handles channel-switching and handovers between
bases without alerting the user.
For operation as a base station or RRM, the parameters in the
Base Station Configuration
pages on the Configuration Main Menu screen should be set appropriately, as described in
the sections that follow.
In addition, the appropriate radio and host parameters must be applied. The radio parameters