Psion Teklogix 9160 G2 - Manual (Page 241)

Psion Teklogix 9160 G2 Wireless Gateway User Manual 219
Chapter 22: The 9160 G2 As Base Station
Overview
22.1 Overview
The 9160 G2 Wireless Gateway can function as either a wired or wireless Base Sta-
tion, or as a Remote Radio Module (RRM), using a radio link and Psion Teklogix
proprietary protocols to facilitate communications with the terminals (see “Radio
Protocols” on page 220).
As a wired base station, the 9160 G2 can communicate with wireless terminals
using Adaptive Polling/Contention Protocol (page 220), 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 terminals using 802.11 WDS.
As an RRM, the operation and timing of the 9160 G2’s radio link to the terminals 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 cel-
lular switching. It is similar in concept to cellular telephone systems. Here, each
base station uses a different radio channel. The terminals monitor the radio link and
automatically switch to the channel with best radio reception. This cellular switch-
ing capability is transparent 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 capability 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 time-
plexed 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 communication. The Psion Teklogix system handles channel-switching and han-
dovers between bases without alerting the user.
For operation as a base station or RRM, the parameters in the Base Station Configu-
ration pages on the Configuration Main Menu screen should be set appropriately, as