WRT Low Power Radio Modem Series
(Preliminary Information)
The WRT Radio Modem Series is currently under development as a range of low cost, short range, data radio modems designed for the low power license-free bands in the 400-900MHz range. It is scheduled to be available for deliveries from April 2008 onwards.
The modems can supplied with RS232, RS485/RS422 or 5V/3.6V interfaces. Programmable options include; RF power 1mW to 25mW, over air data rates of 1200bps - 38.4Kbps in narrow-band or wide-band RF channels and support for a range of protocols.
The modem can be programmed to conform to the new WASP protocol currently being introduced under the auspices of the Water Research Council (WRc) in the UK. The WASP protocol is designed to allow wireless data collection equipment from different manufacturers to work together in a single system. Interoperability trials will be carried out between the WRT Series radios and WASP equipment from other manufacturers over the next few months to ensure full compliance.
- Low cost data radio
- Suitable for licence-exempt use
- 433, 458, 464, 472, 868 & 902MHz versions available
- Versions available for ISM band use (Industrial Scientific & Medical)
- RS232, RS485/RS422 or 3.6V/5V TTL data interface options
- 3.6V, 5V or 12V dc supply
- Low power consumption
- "Listen before Transmit" (LBT) to check channel is clear
- Supports WASP protocol
- Highly sensitive receiver
- Easy configuration using supplied software
The WRT range is suitable for unlicensed wireless data links over distances of up to around 500m. Typical applications include security, data logging, metering, or any similar applications where serial data needs to be transmitted reliably over a short distance.
The WRT is a full transceiver incorporating "Listen before Transmit" capability to check that the channel is clear before transmitting. In some deregulated bands, the inclusion of this feature allows the use of higher transmit powers than is permitted for more basic equipment which just transmits blind.
The WRT data radio has been optimised for low current consumption, making it particularly suitable for operation on remote sites without mains power.
Preliminary WRT Modem Specification
- Cased version
- "D" connector & power plug
Size 55mm x 80mm x 25mm - PCB version
- Plug-in PCB with pins
Size 50mm x 77mm x 18mm - Interface options
- RS232, RS485/RS422, 5VTTL or 3V logic
- Power supply options
- 12V, 5V or 3.6V
- Current consumption
- Standby <50uA
RX <25mA
TX at 25mW <95mA - Frequency ranges
- 433MHz 433.040 - 434.790MHz
458MHz 458.000 - 459.000MHz
464MHz 464.000 - 466.000MHz
472MHz 472.075 - 462.175MHz
868MHz 863.000 - 870.000MHz
902MHz 902.000 - 928.000MHz - Baud rates
- Programmable 1200bps - 38.4kbps
- Programmable Tx power
- 1mW, 10mW & 25mW
- Modes of operation
- Transparent/dumb mode
Store & Forward
MODBUS protocol
WASP protocol
etc. - WASP Option
- 868MHz version programmed for 100kHz channel, 9600bps, Manchester coded with 15kHz deviation.
