TTL, RS232, DCE, DTE......
This is where you can find informations and learn how to connect your Pinguino with a computer or a modem on a serial port.

The Pinguino serial I/O is TTL level ( 0..5V ). It can not be directly connected with an RS232 equipment.
If you want to connect it with a computer, wich is a DTE ( Data Terminal Equipment ), you need to build this converter:

This converter use only discrete components. NPN transistor can be used, such as 2N1711, 2N2222 etc...
Note that the DB9 connector is a female connector because DB9 on Data Terminal Equipment is always a Male connector.
This converter can be powered with a 3,3V or a 5V power supply.

If you want to connect Pinguino with a Modem, wich is a DCE ( Data Communication Equipment ), you need to build this version:

Now the DB9 connector is Male because DB9 on Data Communication equipment is always Female.