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Notice to users/installers using the 24 dBi parabolic dish antenna in conjunction with all Murata RF products. FCC rules limit the use of this antenna, when connected to Murata RF products for point-to-point applications only. It is the responsibility of the installer to ensure that the system is prohibited from being used in point-to-multipoint applications, omni-directional applications, and applications where there are multiple co-located intentional radiators transmitting the same information.
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5RQ Basingstoke, United Kingdom – the Notified Body having performed part or all of the conformity assessment on the product. The WIT2450 to which this declaration relates is in conformity with the essential requirements of the R&TTE directive 1999/5/EC and complies with the following standards and/or other normative documents:...
Murata's high performance, high-reliability RF know-how that has made Murata products the first choice of designers for mission critical applications. With the WIT2450, designers get that same mission critical reliability and robustness but at a price that allows use in a wide variety of cost-sensitive applications.
2.2. Data Transmission The WIT2450 supports two network configurations: point-to-point and point-to- multipoint. In a point-to-point network, one radio is set up as the base station and the other radio is set up as a remote. In a point-to-multipoint network, a star topology is used with the radio set up as a base station acting as the central communications point and all other radios in the network set up as remotes.
To the user application, acknowledgments and retransmissions all take place behind the scenes without the need for user intervention. The WIT2450 has a point-to-point direct mode ( ) which fixes the remote radio’s handle at .
For applications needing guaranteed bandwidth availability, the TDMA operation of the WIT2450 can meet this requirement. In the WIT2450 TDMA scheme, each remote has an assigned time slot during which it can transmit. The base station time slot is set independently of the remote time slots through the Set Base Slot Size command.
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= 15.1 bytes of data per hop. 17.36µs However, the WIT2450 sends data in groups of 4 bytes. Thus, each remote will be able to send 12 bytes of data. If the WIT2450 is using a protocol mode, the packet overhead is stripped off (including start and stop bits) before transmission and does not need to be considered when calculating RF capacity.
WIT2450 can still communicate reliably. Data input to the WIT2450 is broken up by the radio into packets. A 24-bit checksum is attached to each packet to verify that it was correctly received. If the packet is received...
2.3. Modes of Operation 2.3.1. Control and Data Modes The WIT2450 has two modes of operation: Control mode and Data mode. When in Control Mode, the various radio and modem parameters can be modified. When in Data Mode, only data can be transmitted. The default mode is Data Mode. There are two ways to enter Control Mode.
To compensate for the variations in nominal baud rates, the WIT2450 supports an RF flow control mode for point-to-point operation. In this mode, when the receive buffer of the receiving WIT2450 is close to full, the receiving WIT2450 stops acknowledging transmissions. The transmitting radio is set to infinite retries which invokes the RF flow control mode (See Set Packet Attempts Limit in Section 5.3).
2.3.5. Co-Existing with 802.11b Networks In some cases, if a WIT2450-based network is located in close proximity to an 802.11b network, the WIT2450-based network can interfere with the 802.11b network. To avoid causing this interference, the WIT2450 radio supports a selection of hopping patterns that avoid the various 802.11b direct sequence channels.
The remotes may still use transparent mode without formatting to send data to the base, if desired. The WIT2450 supports 10 protocol formats that are described in detail below. The protocol format is selected through the Set Protocol Mode command.
4. MODEM INTERFACE Electrical connection to the WIT2450 is made through a 16-pin male header on the modem module. The signals are 3.3-volt signals and form an RS-232 style asynchronous serial interface. The table below provides the connector pinout. Signal...
Ground. To operate the WIT2450 in this configuration, the Sleep and RTS signals must be tied to ground. These signals are pulled up on the WIT2450 module and if left disconnected will put the radio into sleep mode and RTS will be deasserted. In addition, Power Down Mode (Pin #14) must be tied high.
4.4. Power-On Reset Requirements The WIT2450 has an internal reset circuit that provides a reset signal to the microprocessor if the supply voltage to the WIT2450 falls below 2.7-volts. Operation of the microprocessor at voltages below this voltage is unspecified and can result in corruption of the program memory.
5. MODEM COMMANDS The WIT2450 is configured and controlled through a series of commands. These commands are sent to the modem directly when the modem is in Control Mode when the modem is in Data Mode if the escape sequence is enabled. The command syntax is the same for either method, a one- or two-letter command followed by one or more parameters.
5.2. Network Commands Network commands are used to set up a WIT2450 network and to set radio addressing and configuration. Command Description wb[?|0|1] Set Transceiver Mode 0 = remote (default) 1 = base station wd[?|00-3f] Set Default Handle Used to override automatic handle assignment by the base station...
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Set Hopping Pattern The WIT2450 has 32 preprogrammed hopping patterns (also referred to as network numbers). By using different hopping patterns, nearby or co-located networks can avoid interfering with each other’s transmissions. Even if both networks tried to use the same frequency, on the next hop they would be at different frequencies.
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– 2451.5)MHz. When set to 9, avoids (2429.3 – 2479.1)MHz. When set to A, avoids (2401.7 – 2429.3)MHz and (2458.8 – 2479.1)MHz. If the WIT2450 is to be used in close proximity to 802.11b networks, these alternative hopsets can be used to avoid interfering with the 802.11b networks.
Thus the receiving host will receive just one copy of the transmission. 5.4. Status Commands These commands deal with general interface aspects of the operation of the WIT2450. Command Description zb[?|0|1]...
Display Modified Parameters Recall Factory Defaults Resets the WIT2450 to its factory default state. This is useful for testing purposes or if there is a problem in operation of the system and the configuration is suspect. Use the Store Memory command afterwards if you wish the factory default settings to be remembered the next time you cycle power or reset the radio.
The pinout is provided in Section 7.2. The modems can be used with just a three wire connection. Transmit data, receive data and ground are the three required connections. Note that in this configuration, no flow control is available as the WIT2450 does not support software flow control.
”. Used to enter control mode. wit2400 Toggles local echo. If you are transmitting characters through one modem to another WIT2450, this allows you to see what you are typing. Toggles stream mode. Causes WinCOM to transmit a repeating pattern of characters. Useful for testing.
Can’t enter modem control mode. Make sure the host data rate is correct. The WIT2450 defaults to 9600 bps asynchronous. Evaluation units do not have external access to the CFG_SEL signal; you must use the :wit2410 power-on escape sequence to access modem control mode.
SLEEP) are terminated for proper operation. 9.3. Approved Antennas The WIT2450 is designed to ensure that no antenna other than the one fitted shall be used with the device. The end user must permanently affix the antenna by using an adhesive on the coupling such as Loctite, or ensure the antenna has a unique coupling.
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