Preliminary measurements:  Idle current 3.4 ma, power on current 85.5ma
(10 volt supply through 78M05 regulator)

Some useless product data on the main chip is at:
http://products.sel.sony.com/semi/PDF/CXD2931R-9.pdf

The correct link to the information on the Sony chip,  including the
proprietary $PSNY NMEA sentence:
http://www.ritron.co.th/download/GXB2000.pdf
A short explanation is here:

$PSNY,0,00,05,500,06,06,06,06*14

0 = Preamp status:  0=normal, 1=open, 2=shorted
00=Geodesic system (WGS84) range is 0-25, but no explanation.
05=Angle of elevation limit
500=Speed limit in km/h
06=PDOP limit with DGPS on
06=HDOP limit with DGPS on
06=PDOP limit with DGPS off
06=HDOP limit with DPGS off
*14=checksum

Still trying to figure out the "upload" PT command for initializing -
anyone have a good explanation for "two's complement" notation?

Pictures will be posted when I have time.

More information can be found at http://www.grundlgasse.at/thomas/digitraveler/

NOTE:  Information below is copied from the TAPR APRS sig.
I'm not responsible for any of it...

I got the PDA version, which included a copy of Delorme XMap (esentially
Street Atlas for Palm/PocketPC) . The unit came with three ( ! ) cables for
different PDAs -- however none of them would fit my HP Jornada 520.

For the initial tests, I made a DB9 serial cable assembly. I cut a standard
telephone cord with modular connectors on each end in half. The standard
RJ-11 JACK has 6 contacts in it but the standard phone cords usually have only
the 4 center conductors. Fortunately, the Digitraveller only uses the center
contacts.
The pinout and wiring is ridiculously simple. Hold the modular plug of
the phone cord so the side with the locking tab is facing down and the cable
exit is facing you; i.e. you are looking at the flat side, not the tabbed side
of the plug.
Peer into the clear plastic connector body with a magnifier and inspect
the colors of the individual wires crimped inside the plug. Positions 1 and 6
probably won't have any wire. Counting from the left, note the colors of
positions 2, 3 and 5. At the other end, connect these same pin numbers to the
corresponding pins 2, 3 and 5 of a female DB9 connector. You are done!

The unit started up and ran perfectly as soon as I plugged it into a live
serial port on a PC. I had heard rumors that the pin 4 line of the
Digitraveller cable had to be pulled up to +volts before it would run but this isn't true.
You DO have to have a positive voltage on the incoming (RXD) line however to
make it turn on. In other words, you have to connect both the TXD and RXD
lines of the DB9 (i.e. full two-way serial hookup), even though you don't need
to send any initialization commands to the device. This simple 3-wire serial
hookup will work with most commercial software as-is. See below for null
modem simulated handshaking info, if needed.

More importantly, the simple 3-wire hookup works with the TH-D7 / D700s. I
took a 2.5mm stereo miniplug with a 5' cable molded onto it, and crimped the
the flying leads at the far end into positions 2,3 and 5 of a modular plug.
I used this cable to connect the Digitraveller to a TH-D7's GPS port. Again,
works perfectly. As soon as you turn on the TH-D7 and the outgoing side of the
GPS serial port goes into quiescent +volts state, the Digitraveller turns on
automagically.

This simple 3-wire serial hookup will work with most commercial software
as-is.

> The 'extra' connections on the serial port are NOT needed for most
> canned software. But if someone wants to monitor the data stream with
> other 'standard' tools, or even write their own software to do things,
> having the signals 'pulled true' can make it much easier when you're in
> a crunch. It's simple, especially when it's done when it doesn't matter.

Agreed. For example, Quickbasic respects the status of the handshaking
lines by default. If they aren't asserted corrrectly, programs written in QBasic
will hang on serial port functions if you don't add a bunch of obscure and
poorly documented option switches to the OPEN COMn commands to tell QB to ignore
them.

To avoid these problems, wire the usual null-modem connections on the DB9.
Wire pins 7 and 8 together, and wire pins 1,4 and 6 together.

It will run either on three internal alkaline AAA cells which it eats in
10-15 hours, or from an external source of 5 to 6 VDC fed into a tiny coaxial
power jack about half the size of the ones on common TNCs.

First thing I did when I got mine home was crack it open. You can see where,
on the RJ-12 (telephone-like) connector, the red wire goes to the circuit
board. This is the wire that needs any voltage other than 0V in order to
bring the digitraveler out of suspend mode (off). I took a 7805 5 VDC
regulator and noticed that the ground and output pins will easily solder on
the backside of the power port on the GPS. Took the "input" lead of the 7805
and stretched it out to the side. Got a little piece of wire and connected
the solder point for the red wire to the voltage input of the 7805. The
digitraveler can then be stuck back into it's case with none the wiser.
(just don't hook it to a real serial port, as the stuff coming in on the red
wire will likely be -10v or so and might not react well with the 7805.

Now, I can supply 13.8 VDC on the red wire and it will both hold the GPS in
the "on" mode with the +13.8v AND supply the GPS with 5v of regulated power
through the nomal power port. Note that that GPS doesn't have its own
voltage regulator, and the specs say it needs 6v. 5v from the 7805 appears
to work just fine.