Converting degrees

I have a Fastrax GPS which give me sentences like this one:

So my latitude is 43º 31’ 38.06’’ and my longitude is -5º 37’ 77.04’’ as specified into the datasheet.

So… I’m having 77.04 seconds? Isn’t that 1 minute 17.04 seconds anyway? I’m a bit confused about the way this data is stored and how to convert it to degrees for using it at a GPX.

Can anyone throw a hint?

Please show that piece of the datasheet which lets you conclude this.

But your decoding is false.

You have to read it as 43º 31.3806’ and -5º 37.7704’

43 degrees + 31.3806 minutes
-(5 degrees + 37.7704 minutes)

A google search for GPRMC gives:

It is NMEA sentences.
You can use GPSBabel to convert it to GPX format.