A useful connection (eg, for data logging) using just RXD above and a suitable ground. I soldered wires to R128 and the shield of the existing ethernet port, and am now satisfactorily receiving data from my electricity-usage monitoring device.

NOTE: If a longer open-ended cable is connected to RxD? your NSLU maybe won't boot! Check, that RxD? gets a proper signal at least at boot-time (every time, for example, a gps-receiver isn't connected to the soldered-on RxD2?-cable, it hangs somewhere during redboot-init. This was at least observed with two different NSLU2 boxes).

Pin 1 is the left-hand pin and marked on the NSLU2 PCB.

NB: In the photo above, a set of header pins has been attached to J2. As sold, J2 consists only of a series of solder filled holes in the PCB. If you wish to put a header on then you must remove the solder first.

There is a second serial port on the NSLU2 but only receive and CTS are connected. It is not possible to connect to the transmit line. The connection points are on the back of the NSLU2 PCB.

By default, both RedBoot and the Linux kernel use 115200,8,N,1 settings.

By default, both Redboot and the Linux kernel use 115200,8,N,1 settings.

Set DTR drop time to 0, and "modem has DCD line" to no, unless you know that your serial adapter ties DCD to DTR.

Make sure that your terminal program does not send a modem init string and that you have set it to software flow control, not hardware.

See HowTo.AddASerialPort for details on adding a serial converter to allow usage of the serial port.

[http://groups.yahoo.com/group/nslu2-linux/message/87]

Location of the second receive only serial port:

[http://groups.yahoo.com/group/nslu2-linux/message/87]

Pinout for the second receive only serial port:

RXD - Right side of R128
RTS - NC
CTS - Left side of R142
TXD - NC

[http://groups.yahoo.com/group/nslu2-linux/message/488]

Pin 1 is the left-hand pin.

NB: In the photo above, a set of header pins has been attached to J2. As sold, J2 consists only of a series of solder pads.

As I said, you need an RS232 level shifter (to convert TTL levels to +/-12V as needed by RS232 serial ports. I believe both Maxim

Pin 1 - 3.3V (pin 1 has a white stripe next to it)
Pin 2 - RXD (from serial terminal program to NSLU2)
Pin 3 - TXD (from NSLU2 to serial terminal program)\\

+/-12V as needed by RS232? serial ports. I believe both Maxim

[http://groups.yahoo.com/group/nslu2-linux/message/87]

Here's the pinout for the "J2" serial port:

Pin 1 - 3.3V Pin 2 - RXD (from serial terminal program to NSLU2) Pin 3 - TXD (from NSLU2 to serial terminal program) Pin 4 - GND

By default, both Redboot and the Linux kernel use 115200,8,n,1 settings.

As I said, you need an RS232? level shifter (to convert TTL levels to +/-12V as needed by RS232? serial ports. I believe both Maxxim (sp?) and Dallas Semiconductor sell the chips. Or, the converters could be there as 'off the shelf' adapters (for developers) I suppose.