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The RF modem uses the CC1000 RF transceiver. A Pair of RF modems function as a wireless replacement for an ordinary RS-232 serial cable. The modem will function with equipment and software supporting hardware handshaking and half dupex communication. The function of the modem is completely transparent.
The RF modem communicates with a PC or other RS-232 devices over an RS-232 link. In transmit mode, the modem reads data from the RS-232 serial interface, creates packets containing data, and transmit these packets over the RF link. In receive mode, it looks for valid packets. When one is received, the data contained within the packet is extracted and sent to the attached RS-232 device or PC.
In most cases, an RS-232 serial port is full duplex. As the RF link is a half duplex link (data cannot travel in both directions at the same time), some form of data flow control is necessary. The RF modem is designed to use hardware handshaking to tell the PC/device is able to receive data when it is not. Communication between the PC/device and the RF modem occurs at 57600 baud, 8 data bits, 1 stop bit, and no parity.
Th RF modem can be used to replace an RS-232 cable with a wireless link. Hardware handshaking must be used. The range of the system depends on the RF frequency, data rate, output power and type of antena used. Environmental conditions will also affect the range; interference from the nearby radio sources may reduce range drastically. If the system is used indoors, a phenomenon known as multi path fading may be a problem, but can usually be resolved by moving the RF modem around a bit or changing the RF frequency.
Three LEDs on the RF modem are used as status indicators. The green LED (D2) functions as a power on indicator, the yellow LED (D4) is lit when the modem is transmitting RF data and the red LED (D3) is lit when the modem is receiving RF data.
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