Psion Teklogix 9160 G2, Руководство пользователя, Страница: 246 / 436

Chapter 22: The 9160 G2 As Base Station
Radio Protocols
222 Psion Teklogix 9160 G2 Wireless Gateway User Manual
are found in the Radio pages for Narrow Band radios, as described in Section 22.3.1. The
parameters for the hosts are described in “Section 22.4.4 Hosts Menu” on page 246.
Note: The 9160 G2 main parameters should first be set up as described in Chapter 4:
“Quick Steps For Setup And Launch” and Chapter 5: “Configuring Basic Set-
tings”. For details on the RF protocols, see the following sections.
22.2 Radio Protocols
RF protocols allow mobile computers to communicate with a base station by sharing the use
of a radio channel in an efficient way. Psion Teklogix systems use one of two types of RF
protocols: the Psion Teklogix Adaptive Polling/Contention protocol or the non-proprietary
IEEE 802.11 protocol.
When used as a base station or RRM, the 9160 G2 uses the Adaptive Polling/Contention pro-
tocol. The 9160 G2 supports simultaneous base station and 802.11 access point operation.
22.2.1 Adaptive Polling/Contention Protocol
The Adaptive Polling/Contention protocol is always used on Narrow Band radio systems with
baud rates of up to 19.2 kb/s, and may also be used on Spread Spectrum systems at higher rates.
Mobile computers operating with this protocol do not transmit unless they receive polls
from the 9160 G2. Mobile computers are generally polled en masse. Following each poll,
groups of mobile computers are assigned response windows in which they may respond to
the poll. If a “collision” occurs—more than one mobile computer attempts to respond in a
particular window—the 9160 G2 that is polling divides and reassigns that group until the
colliding mobile computers can respond without a collision.
Adaptive features of this protocol allow the response windows to be adjusted to accommo-
date high or low RF traffic conditions, and to prevent data from being queued too long when
a particular mobile computer has a burst of data to send or receive.
Systems using adaptive polling/contention can use the cellular option so that mobile com-
puter operators can roam the site, maintaining uninterrupted communication as they pass
between coverage areas.
If cellular base is not enabled, a “RESET: Press Enter” message appears on the mobile com-
puter screen each time an operator moves from one base station coverage area to another.
22.3 Narrow Band Menus
22.3.1 Narrow Band Radio Configuration Settings
When you select the Radio sub-menu from the Narrow Band menu options, the 9160 G2
displays the Narrow Band Radio Configuration Settings of the operating mode for which the