I have this Ublox GPS receiver http://www.hobbytronics.co.uk/gps/ublox-gps-neo6m
I'm using it with U-center v8.29 running on a laptop with "Prolific" USB-RS232 interface. The computer port is configured to the default 9600 8-bit no parity 1-stop.
Board is powered off 5V PSU (specification for this board is 3.3 - 6V)
When I connect to the GPS the connection indicator goes green, I think the PC must be communicating with the module ok because initially current draw is very low, but when I send the command to activate the receiver the current jumps up to approx 35mA which is the specified current for the module.
However, I get no valid data: the status indicator at the bottom of the U-center screen shows COM4 9600, which is the same as my PC port setting, but the indicator is repeatedly flashing red, not green as it should, and I get nothing displayed in any of the GPS windows.
The antenna has a good view of the sky.
I have an RS232 protocol analyser (an old Thurlby DA100) and an oscilloscope which I have used to monitor the RS232 output from the module. The analyser confirms 9600 baud but just shows bursts of garbage and framing errors in the data display. The scope shows regular bursts of data (mark +5V space 0V) about one burst per second.
It appears that the module is just sending corrupt data.
The module spec says the TX serial connection is compatible with 3.3V/5V systems, and my RS232 converter has a 5V interface. However I have noticed that the spec also says RX input max 3.6V - it seems strange if the serial interface is compatible with 5V one way but not the other.
I'm new to using these modules (but not new to electronics) and I've exhausted all the steps I can think of, short of trying a new module. Is it likely that I have a faulty one or is there anything else I should try first?
Be grateful for any pointers.