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Technical support
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User’s Manual
AW900R2-PAIR
Operational summary
RS-232 is a point-to-point serial data connection that requires just three wires:
Transmit Data, Receive Data and Ground. Because there is no handshake involved,
both ends must be configured for matching data timing and protocol or communica-
tion will not occur. Also, it is possible to lose data if the receiving device cannot
keep up with the sending device. The AW900R2-PAIR supports data rates from 9600
Baud to 115,200 Baud and has a 4 KB data buffer. When properly configured, this
pair of radios behave just like an RS-232 cable but without the length constraint and
without a physical wire.
The AW900R2-PAIR is shipped from the factory pre-configured to meet most user’s
needs. If this configuration works for you, most of the rest of the information in this
manual is not relevant. The pre-configuration settings are:
• One radio is the Access Point or master and the other radio is the Subscriber
Unit or client.
• The RF frequency channel will automatically change to avoid interference.
• The Network ID and AES Encryption Key are all zeros.
• The serial port settings are 115200 Baud, 8 data bits, 2 stop bits, no parity.
• Tuning parameters are optimized for minimum latency: Next Byte Delay - 00,
Minimum Packet Size - 01, Maximum Packet Size - 024. These parameters are
explained on page 7.
AW900R2 radios may be re-configured by removing the cover and connecting a PC
to a USB port on the module inside. A utility program from AvaLAN is then run on
the PC that can set the configuration and check the link status. The LED display on
the inside module is also a very useful indicator of the condition of the wireless
connection.
The access point (AP) automatically scans for the best of the 12 available radio
frequency channels, encrypts RS-232 data received, and transmits it wirelessly to
the subscriber unit (SU). The AP is constantly monitoring the radio link and can
automatically change the channel if performance is degraded due to interference.
If two AP units from two different bridges are very close to one another, they may
interfere if operating on adjacent frequency channels. Place them at least 10 feet
apart or manually select non-adjacent channels for their operation. Also, the two
radios in the bridge should be placed at least 10 feet apart to avoid overloading the
radio receivers.
At each end of the wireless bridge, the RS-232 device wired to the AW900R2-PAIR
must have its transmit signal connected to the radio’s receive and vice versa. Mis-
wiring will not cause damage, but will prevent communication.
