FHSS Transceiver

Short-range wireless in a miniature package

One of the surging technologies of the last two years has been in wireless products. Cities are scrambling to set up wireless zones in business areas and airports, and more simple children’s toys have the added feature of radio control. Driving this paradigm shift is the shrinking size and cost of transceiver components.

To meet the growing demand on OEMs creating local RF networks where tight space, low power and limited resources are the biggest concerns, AeroComm Inc, Lenexa, KS, has introduced a mini all-inclusive 900 MHz FHSS transceiver. They can replace a mile of cable, even in harsh industrial conditions. Popular concerns — such as size, speed, range, power, reliability and cost — are addressed, making wireless practical for most high-volume industrial applications.

The 1-in. square AC4490-1x1 module is intended to be so comprehensive that engineers of varying RF experience add full wireless capability to their designs with minimal effort. The modules contain the company’s RF232 embedded transparent protocol, which supports plug-and-play installation. Over-the-air issues are managed in the firmware to synchronize, hop, gain acknowledgements, send retries, detect errors, address messages, secure transmissions and other features unique to RF. As each transceiver receives raw data, it manages over-the-air protocol to assure successful communication. Headers, data packet length and CRCs are not needed. RF232 supports point-to-pint or point-to-multipoint, client/server or peer-to-peer configurations. One can broadcast communication to all transceivers or address packets to a specific destination using unique MAC addresses embedded in each transceiver.

Within the compact size, these transceivers feature up to 115.2 Kbps serial interface data rate, with 1 to 10 mW variable output power. Local or remote I/Os include two digital input lines with two digital output lines, and 1 A/D input line with 1 D/A output line. Industrial temperature durability runs from -40° to 80°C. All components, including firmware, are integrated into sleek, multi-chip module construction. Development is straightforward: modules and antennas are simply mounted into place (via hand-solder or surface-mounted with pick-and-place equipment), and then powered on. No special host software is required, as the 1x1s directly appear to the system as cables. The standard TTL serial interface provides bi-directional communication in point-to-point, point-to-multipoint or multi-to-multi networks. A number of on-the-fly control commands accommodate varying wireless applications. Using field-proven proprietary FHSS technology, 1x1s provide interference rejection, enable co-located system operation, increase output power, and maintain data integrity.

The AC4490-1x1 is suited for industrial and commercial battery-powered applications, such as meter-reading, building controls, point of sale and home automation. The 1x1 can be used in portable, mobile and fixed applications.

"The 1x1 is our response to market demand for more powerful features in ever-smaller, less expensive transceivers," says AeroComm CEO Michael Varady. "By providing a robust product at a fraction of the size and price of comparable modules, we aim to make RF practical for any application."

—RM