GPS module + PIC

[flotulopex]

Hello,

I'm trying to communicate with a GPS module http://www.futurlec.com/GPS.shtml.

Before I connect it to a PIC+LCD, I try to communicate with the GPS module via a PC terminal.

Unfortunately, I can't get any "understandable" message from the module; I might receive SIRF information instead of NMEA messages, I don't know.

This is what I see on my terminal:
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=4175&stc=1&d=127083345 4">

If my guess is right, I would need to switch from SIRF to NMEA protocol. There are to examples hereunder in the doc (full doc attached).
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=4174&stc=1&d=127083336 4">

I don't understand how to calculate the checksum.

I found a cool checksum calculator, HashCalc from SlavaSoft Inc. But I can't find a similar checksum corresponding to both examples.

Can someone tell me in "simple words" how the checksum in both samples above have been calculated and the exact string I would have to send the data to the module?

Is it "$PSRF100,1,4800,8,1,0*0D0A" or "$PSRF100,1,4800,8,1,0*0D,0A" or "$PSRF100,1,4800,8,1,0*<0D><0A>" or anything else?

I've spent quite a few hours on this one and no success so far so any help or info is very welcome