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WinCE handhelds running Pocket PC offer significant compute capactity in a readily programmable environment.  Unfortunately, the companies that build the handhelds decided to use a proprietary connector for the serial port.  This page describes how to get around the cabling issues and options for Compaq's iPaq and HP's Jornada Pocket PC handhelds. 

Compaq iPaq

There are three choices for the Compaq iPaq interface to the BrainStem The first and easiest choice is to purchase the RS-232 Serial Cable (Compaq P/N 236250-001).  This cable can be connected between the iPaq and the BrainStem Interface Assembly. 

RS-232 Serial Cable interface option

The second choice is to use Compaq's Serial Autosync Cable (P/N 191008-B21).  This cable must plug into a DB9 null modem male-to-male adapter , which then plugs into the Windows BrainStem Interface Cable. 

Serial Autosync Cable and null adapter interface option

The third choice is to take one of the two Compaq cables mentioned previously and hack it into the Acroname Level Shifter Kit along with the 4-Pin Connector to build up a custom cable.  While not the easiest, this choice allows you to set the cable lengths and possibly thread it through whatever you are using the BrainStem for (such as a PPRK robot). 

HP Jornada

There are two choices for the HP Jornada Pocket PC interface to the BrainStem.  The first and easiest choice is to use the serial sync cable provided with your handheld and a DB9 null modem male-to-male adapter.  This then plugs into a BrainStem Interface Assembly. 

The second choice is to take one of the HP cables mentioned previously and hack it into the Acroname Level Shifter Kit along with the 4-Pin Connector to build up a custom cable.  While not the easiest, this choice enables you to set the cable lengths and possibly thread it through whatever you are using the BrainStem for (such as a PPRK robot). 

Dell Axim

Connecting a BrainStem to the Dell Axim Pocket PC requires a modification to the BrainStem Serial Interface Connector.  It requires a jumper wire to be soldered between two of the pins on the DB9 header.  A picture of a connector with the modification is shown below:

Serial Interface Connector modified for use with Dell Axim

Use a soldering iron to melt the solder in one pin, then slide in a jumper wire.  Repeat the process to connect the other end of the jumper wire to the other pin.  Once modified, the connector will still work with a normal RS-232 connection on a host computer. 

Connect the serial sync cable provided with your Dell Axim to a DB9 null modem male-to-male adapter.  This then plugs into a BrainStem Interface Assembly.  with the modified connector. 

Building a Null Modem Adapter

A null modem adapter is easy to build.  It requires connecting three wires between two male DB-9 connectors. 

Necessary connections for building a null modem cable.

This passes through the ground connection on pins 5 and swaps the TX and RX lines on 2 and 3. 

Settings for WinCE

The default settings for the various BrainStem software and the firmware work without modifications.  If you are experiencing trouble with this interface, you may want to remove the console.config file (if present) and do a physical reset of the BrainStem board to restore defaults. 

Related Links:

Acroname Serial Interface Standard

BrainStem to Host Interface Cable Details and Information