If you want to access all of the features on your
computer's serial port, this serial adapter is for you. The adapter
allows you to connect your 3-5.5 V logic circuits to a COM port,
which operates on higher and negative voltages (EIA-232, similar to the
older RS-232 standard). The adapter is available fully assembled with
male header pins facing down for use with prototyping boards and
breadboards, or as a partial kit as shown to the right. The partial kit
offers more flexibility if you do not need all of the header pins or if
you want to install them on the other side of the board (or not at all).
This adapter distinguishes itself from most
competing units through its five drivers and three receivers, which give
you access to all eight signal lines on a DB9 connector (the ninth pin
is ground). This means that in addition to standard serial
communication, you project can also use all of the handshaking lines and
status lines. Even if you do not use them for their intended purposes,
you might find it convenient to be able to reset your processor using
one of the extra lines. A connection detection line gives your project
additional options for responding to a physical connection to a serial
port. All of this connectivity comes in a compact package that is less
than twice the size of the DB9 connector alone.
The first nine pins on the deluxe serial adapter
correspond to the same nine pins on a COM port DB9 connector. The
additional pins are the logic supply voltage, the serial connection
detection pin, and an inverted version of the transmit line (which can
be useful if, for instance, you have a positive-edge triggered interrupt
that you want to fire in response to the beginning of the start bit).
The TX line and RX lines are labeled from the computer's perspective, so
the TX pin has data transmitted by the computer that should be connected
to your project's receive input.
||1.30" x 1.22"
I/O voltage levels:
||3 – 5.5 V
||"Data carrier detect"
||Asynchronous serial data receive
||Asynchronous serial data transmit (idle
||"Data terminal ready" control
output (often used with DSR)
||"Data set ready" control input
(often used with DTR)
||"Ready to send" control output
(often used with CTS)
||"Clear to send" control input
(often used with RTS)
||"Ring indicator" control input
||Logic supply voltage (3 – 5.5 V,
||Serial port detection pin, high if serial
||Asynchronous serial data transmit,
inverted (idle low)