Something is different with GPS data between 436, HP1 and SDS100

[Hit_Factor]

I built one with the TTL, got it right the next time with serial. GPS should work with any cable. To charge scanner simultaneously you need the heaviest gauge cable you can find for red and black.

If its not working cut off the ends, check your work and try again.

 

[buddrousa]

The same factory Uniden GPS with factory cables works on BCD325P2, BCD436, and SDS100.

 

[nessnet]

The same factory Uniden GPS with factory cables works on BCD325P2, BCD436, and SDS100.

They are the same puck, but the Amazon one (earlier link) doesn't have a Uniden sticker on it.

 

[jonwienke]

The SDS100 uses RS232 signaling between the ID pin and ground. You can't use the USB port to power the GPS, the +5V pin is input only. Powering the GPS requires a separate connection. Most new GPS modules available output data at 9600 baud, not 4800. Set your scanner accordingly. Also, the modules that RX multiple GNSS (e.g. GPS and GLONASS) generally start all NMEA sentences with $GN instead of $GP, and have to have settings changed to output $GP before the Unidens will parse the data.

 

[buddrousa]

That is why I use a Uniden or a Jonwienke built GPS units only.

 

[ra7850]

That is why I use a Uniden or a Jonwienke built GPS units only.

I agree. I have 2 units that Jonwienke has modified. I tried the build your own route but was unsuccessful.

 

[buddrousa]

But my point was if it works for the BCD436HP it will work with the SDS100 if the cable is correct it is not the scanners fault.

 

[jjlongworth]

Hello all... I've solved the problem!

First, sorry for the delayed reply. We had a very sudden death in the family from Covid-19. Please take the precautions seriously. It took one of my parents in a matter of hours.

Just to recap, I was attempting to use a DeLorme handheld GPS with my SDS100 and could not get it to work despite the fact that I have used it successfully with my BCD436. As many of you confirmed, there are only two connections required for the SDS100: GND and TXD. These are connected to Pins 1 & 2 of the USB mini jack of the scanner. However, the piece that was missing is that the GPS would not output on the TXD line if the RXD pin was floating. I believe that under normal circumstances, the RXD line would be held high by the receive (slave) side, but since Uniden decided to bastardize the standard USB connector by using the ID pin as the TXD in, the RXD pin on the GPS side was left dangling. The solution was to add 10k pull-up resistor +5v to the RXD line on the GPS side.

This gets back to one of my original rants: don't take a standard connector and use it for some goofy application. Uniden should have left well enough alone and continued to use the Hirose connector (used on other models) instead of replacing it with the micro USB that no one seems to understand what it does. The Hirose connector used TXD, RXD, GND and, I think, RTS.