In replying to your post I am hoping to save you a bit of time & a few headaches.
Like you I am building a Netduino project which communicates with a serial device. In my case I am connecting to an analog modem with an RS-232 serial interface. This modem has a female connector on it and is intended to connect to the serial port on a PC (which has a male connector) using a straight-through 9-pin serial cable (male on one end, female on the other).
Many of the adapter devices I've investigated, which convert from TTL-level voltages to RS-232 level voltages (i.e. 3.3V/0V or 5V/0V to +12V/-12V), are built with a female DB-9 connector. I guess most of the developers of these adapters assume that the micro controller device (i.e. Netduino or Arduino) will be connected to a PC and be controlled by the PC, rather than the micro controller device being the master and controlling something else.
Anyway, I have found that SparkFun Electronics has several devices which you can use to do the conversion:
- RS232 Shifter Board Kit (PRT-00133); has female connector (you need to get out your soldering gun to build it)
- RS232 Shifter (PRT-08780); has no connector - you can buy one separately & solder it on
- RS232 Shifter (PRT-00449); has female connector
- MAX3232 Breakout (BOB-11189); no connector
- RS232 Shield (DEV-11958); has female connector
I also found an RS232 / TTL converter on eBay which has a MALE connector on it:
I ordered the eBay item and received it about 2 weeks after placing the order. I haven't yet incorporated it into my project but will let you know, if you're interested, when I do.