If you are unable to communicate with your Handy Board at all, here is a sequence to test your serial line connection.
First, set up just your Interface/Charger Board, the DC adapter, and the modem cable that connects the Interface/Charger Board to your computer:
The DC adapter should be plugged into the wall outlet, and the red PWR LED on the Interface/Charger Baord should be on.
We will perform the testing with the assistance of HyperTerminal, a communications program that is bundled with Windows. You can find it in the Start menu under Programs/Accessories.
If your PC does not have HyperTerminal installed, you can download it from here.
Double click the Hypertrm application, and you will be presented with a New Connection dialog, shown below. You must type a name for the connection; it doesn't matter what you enter. In the example, the connection name test connection is entered:
After clicking OK, you will then have a dialog for choosing the modem. In this case, we want a Direct to Com 1 (or Direct to Com 2, Com 3, etc.) connection. Make sure to choose the serial port you think your Handy Board is connected to.
Next, we get a final dialog for the serial Port Settings. Two of the defaults must be changed: make sure to select 300 bits per second (the first field), and "None" for Flow control (the last field). Before choosing OK, the dialog should look like this:
Finally, you will get to the main HyperTerminal screen, which looks like this:
At this point, look at the green SER LED on your Interface/Charger Board. It should be on steadily. If it's not on, there is either:
Assuming all is well so far, now type a few characters on your keyboard while looking at the green SER LED. Each time you strike a key, you should see a brief flash of the green LED.
If you get the flashes, one per keystroke, then you have established the following:
It's still possible that the back-path, from the Interface/Charger Board to the PC, is broken. The next test will verify that your PC can communicate bi-directionally with the Handy Board.
To do this, you will need the RJ11 telephone cable that connects from the Serial Interface/Charger Board to the Handy Board, a staple from a common desk stapler, and a bit of manual dexterity.
First, plug one end of the RJ11 cable into the Interface/Charger Board. Leave the other end dangling:
Next, bend the staple into a "U" shape, with about one-eighth inch between the two legs of the U. The spacing between the legs of the "U" should be the width of the outer two of of the four pins on the RJ11 plug, like this:
Now, press the clip into those outer two metal connections of the RJ11 plug, and while the clip is pressed against those connections, type some keystrokes on your keyboard. You should see what you type echoed back on your screen. In other words, when the clip is not attached, when you type you shouldn't see anything on your screen (just the flashing of the green SER LED on the Interface/Charger Board). But when the clip is pressed against the outer two metal connections of the RJ11, then your typing is echoed back to HyperTerminal and displayed on the screen.
If you're having trouble pressing the clip into the RJ11 plug with one hand, while hitting some keys with the other, please get a friend to help you.
If this all works, then your serial line system is basically completely tested. It's established that:
If you can't get the loopback test to work, but you do see the green flashing LED on keystrokes, then any of the following could be wrong: