User's Manual

Page 49
E Series Data Radio – User Manual
© Copyright 2005 Trio DataCom Pty. Ltd.
Tx/Rx (Frequency) Trim
The currently selected frequency trim, which is common to both
transmitter and receiver, is displayed in the main window below
the button in Hz. The frequency trim can be adjusted live by
selecting this button which displays a dialogue box. The up/down
keys can be used to select the required frequency offset in steps
pre-determined by the radio modem. Selecting OK will retain
the frequency trim setting. Note that although the frequency
trim has been adjusted it must be written to NVRAM using the
modem “Write” function to ensure it is retained after the modem is
rebooted.
This facility permits correction for drifts in the frequency reference
caused by component aging. For example, a standard crystal
may vary in fundamental frequency operation over 1 year by one
part per million. An adjustment range of ± 10ppm, displayed in Hz,
has been allowed for and if this is insufficient the unit should be
returned to the dealer/factory for re-calibration.
Advanced
This button permits setting of advanced features. When selected
a dialogue box appears which permits configuration of the type of
received data clock alignment method.
In the case of full duplex units the receiver is always active and
is not interrupted by transmissions from the unit as would be the
case for half duplex units. In this situation it is not necessary, or
desirable in the case of a base station, for the recovered data clock
alignment to be remembered between bursts of received signals.
In this situation the “Receiver Full Duplex” check box to the left
should be selected.
Note: For half duplex units the “Receiver Full Duplex” check box
System Parameters
This section of the main window configures the PTT control,
collision avoidance, stream setup for routing of data, advanced
features and provides unit information.
PTT (Press To Talk) Control
RF transmission can be configured to occur permanently,
automatically on data received at Port A or Port B, or RTS being
asserted on Port A or Port B. A PTT timeout facility can be
configured to limit the period for which the transmitter is enabled.
Each option is selected by setting the control to the left of the
description on the main window. When PTT is active the “Tx” LED
on the unit is illuminated and RF power is being fed to the antenna.
Permanent Tx
This will cause the transmitter to be permanently enabled (keyed)
and displays another dialogue box warning the user that the
transmitter will be energised immediately after the configuration
is written to the unit. Selecting OK confirms this setting. The other
PTT selections are disabled when this option is selected.
Note: This option is only available for full duplex units when being
programmed locally.
Auto On Data
This will cause the transmitter to be enabled (keyed) automatically
on data received at Port A or Port B and included in a complete
frame for transmission over the radio channel. The maximum
period for which the transmitter will be enabled is limited by the
PTT timeout setting.
From Port A RTS
This will cause the transmitter to be enabled (keyed) on Port A RTS
being asserted. The maximum period for which the transmitter will
be enabled is limited by the PTT timeout setting. Applications which
rely on establishing a link ahead of data being transferred require
this method of activation.
From Port B RTS
This will cause the transmitter to be enabled (keyed) on Port B
RTS being asserted. The maximum period for which the transmitter
will be enabled is limited by the PTT timeout setting. Applications
which rely on establishing a link ahead of data being transferred
In the case of 25kHz channel radio modems the presently
supported modulation schemes include:
• 19200 25kHz ACA E Series. This is a new 19200bps
modulation scheme available in E-Series products which
supports a significantly reduced delay between detection of
a valid RF carrier signal and demodulation of user data.
• 9600 25kHz ACA D Series. This is a current 9600bps
modulation scheme used in the D Series products to
provide backward compatibility.
Part I – TVIEW+ Management Suite - Programmer