Although the RS232 spec does define specific connector types, genders, and pin allocations, too many people seem to find it too inconvenient to actually read the spec - with the result that you cannot now rely on the connector gender as any indication of how it's wired. :-(

See rant here: http://www.8052.com/forum/read.phtml?id=46426

However, the pin assignments on PC COM ports are well-known^[1], and you presumably know the pinout of your MCU board. You therefore need to find the pinout for this "other device" - try looking in its Manual, or on the manufacturer's website.

You should also check the cable that works between the PC and the "other device" to see if it has any cross-overs or loop-backs.
http://www.epanorama.net/documents...ables.html

Other things to consider (that Manual and/or website should help):

Do you have all the comms settings the same; ie, Baud rate, start bits, data bits, stop bits, parity, etc?

Does the "other device" require hardware flow control, or any specific states on the control lines, or even some specific event(s) on the control lines to wake it up?

Does the "other device" require any special command sequence to wake it up?

Do you use any special software on the PC to talk to this device - if so, there may be some special protocol.

Are you sure that the "other device" is truly RS232? If it hasn't used a proper RS232 transciever, but some cheap bodge instead, it is quite possible that it only works with your PC by pure luck!


[1] beware that pins 2&3 have their functions transposed between 25- and 9-way PC COM ports