Radiometrix Ltd.

UHF FM Radio Packet Modem

page 10

The RPM3 supports three rates, max (17kbps), slots (3.6kbps) and slotsw (1.8bps), of over-air throughput.

possible. For host baud rates above 9600bps, data is transmitted continuously with minimal

delay between sequential packets. When this occurs, there is effectively no airtime for another

pair, operating in close proximity, to transmit without causing collisions. The maximum over-air

throughput that can be achieved is 17kbps with ACK and 28kbps without ACK..

Figure 8: RPM3 streaming data

with ACK at maximum throughput

In Figure 8, RS232 serial data bytes accumulated in the receive buffer is transmitted as two 10kbps

bursts by transmitting RPM3 with gaps just enough to receive ACK from receiving RPM3.

Figure

For continuous data transmission at baud rates above 9600bps (with ACK) or 19200bps (without ACK),

hardware flow control should be used to prevent the host from causing receive buffer overrun errors.

RPM3 will signal CTS pin to stop/allow the host depending on its Receiver Buffer level.