996T Pinout for rear Serial Port?

[Universaldecoder]

Anyone know? I've search prior posts and could not find this info (although it's asked a couple of times).

 

[dougjgray]

Havent seen it any where but it should be the same as a Host Com Port on a PC so the GPS will work. Might try googling for that.

Heres what I found For a PC:

http://www.technick.net/public/code/cp_dpage.php?aiocp_dp=pinconser_pc_9pin

 

[Butelsoftware]

You only need to connect pin 2 (txd), 3(rxd) and 5 (gnd).

If your PC has a 9 pin serial the cable diagram is:

PC ------------------------ Scanner
9 pin female ------------ 9 pin female

2 ------------------------- 3
3 ------------------------- 2
5 ------------------------- 5

 

[dwessman]

Nevermind

Duplicate of above - deleted.

 

[Universaldecoder]

Dedicated SirF III GPS for BCD996T

Thanks. Does the BCD996T transmit data back to the GPS unit? What I am doing is connecting a serial "mouse" gps.

http://www.usglobalsat.com/p-57-br-355-gps.aspx

What I was looking for was a pin on the 996T that provided +5 volts, and I found it to be the #3 pin. However it was -5 volts, and then I realized that this was used for signal.

The BR-355 draws 80 mA typically.

Anyhow I ended up soldering in a DC-DC converter that takes 12 volts in and spews out 5 volts. It's a bit bulky - about the size of a cigarette lighter adaptor. The space in my dash is pretty crowded as it is. Hope it all fits!

Here is a another option for a DC-DC converter, but I was eager to get things installed before the temps here in Michigan began dropping again.

http://www.dimensionengineering.com/DE-SW050.htm

You could probably stick this inside the BCD 996T along with this

http://www.usglobalsat.com/p-49-et-332-sirf-iii.aspx

and drill out a tiny hole for an antenna cable. It would be a real neat install - I'd be wary of rf interference though.

 

[Butelsoftware]

Funny is that inside the scanner one of the pins is actually marked V_GPS but is not connected.

Not sure where the picture came from but it shows a sample of using the 5 volt regulator.

Gommert
www.butelsoftware.com

 

[Universaldecoder]

Gommert,

Have you had a look inside a 996T - is that an existing regulator or was it added?

 

[Butelsoftware]

It was added, I used this picture to modify one of my bct15's for use with a gps mouse.

Gommert
www.butelsoftware.com

 

[Universaldecoder]

It was added, I used this picture to modify one of my bct15's for use with a gps mouse.

Gommert
www.butelsoftware.com

Did you use the same regulator or a different one? If not, would you happen to have the make and model number

 

[Butelsoftware]

I used the 7805, is a very common and cheap regulator.

Gommert
www.butelsoftware.com

 

[Universaldecoder]

Thank you, Gommert. This is a nice alternative, and I am seriously considering it due to the fact that I do not have much room inside my car's dash.

FYI to all, Radio Shack carries the 7805, part no is 276-1770, $1.59 USD.

For reference I've attached info on a 7805:

 

[slicerwizard]

I don't see any current limiting components in that photo. Adding some would be a good idea.

 

[Universaldecoder]

I don't see any current limiting components in that photo. Adding some would be a good idea.

Hello, the STE has internal current limiting. Incredible what they can pack into these little things. I think, but am not sure, the RS also has this feature.

If the above is not what you had in mind please elaborate! I'm gun ho about trying this out soon - and I hate the smell of burning ic's.

 

[Universaldecoder]

Gommert,

Is that a form of insulation between the board and the regulator in the picture above?

 

[jonny290]

Shouldn't be - the terminal on 3 pin regulators is ground.

7805 for 5v, 7806 for 6v

I wouldn't worry about current limiting unless you play around with half-baked serial cables with wires twisted up. Put a .5A fuse in series with the regulator output if you're worried about it.

 

[Universaldecoder]

Yippeeee.....

Tis done! Here is my mod! Just reinstalled the radio. The mod itself took less than 15 minutes. Re-install even faster since it's a balmy 67 degrees outside.

I love that SirF III chipset. Acquisition time is fast, and solid. So this all began with wanting to do away with a handheld GPS, and going with a dedicated serial GPS mouse.

This was fun, and I learned a lot. Thanks all.

Now what.......

(Crp, I'm gonna pay for this tomorrow at work).