Advanced Wireless Data Communications


Q The SYS (System) LED on my radio is flashing and radio is not working - what is wrong?

A - The flashing SYS LED is an error code. Firstly the BUSY led will come on and the SYS led will flash a number of times, the BUSY led will then go out again and if the fault persists the procedure will be repeated. The error number can be determined by counting the number of times the SYS led flashes while the BUSY led is on. There is a product specific error de-code table in each product manual.

Q The radio keeps adding extra characters to the end of received messages. What are these and how can I get rid of them?

A - This is normal and nearly all data radios will exhibit this behaviour to some extent. When a transmission ends, the received RF level drops down into the noise and, because it takes a finite time for the radio to detect the drop in level, a short burst of this noise is passed through the decoder before the system mutes. This squelch noise is the same as the burst of noise that can be heard on a voice radio at the end of transmissions. The noise burst typically decodes to 2 or 3 spurious characters at the end of each received transmission. By enabling packet mode our radios can automatically strip these extra characters back off again before the messages are passed to the serial port.

Q My radio appears to be drawing a lot more current from the supply than is indicated in the data sheets. Why is this?

A - Check that the antenna system and coaxial feeder cables are in good condition. If the transmitter output stage does not see a good 50 ohm load, then it can draw up to twice the normal current. The device should not be damaged by such a mismatch, but the radio may become very hot and RF power will not be correctly transferred to the antenna.