I am new to the locating hardware side of embedded programming and so after being completely overwhelmed with all the choices out there (pc104, custom boards, a zillion option for each board, volume discounts, devel kits, ahhh!!) I am asking here for some direction.

Basically, I must find a new motherboard and (most likely) re-implement the program logic. Rewriting this in C/C++/Java/C#/Pascal/BASIC is not a problem for me. so my real problem is finding the hardware. This motherboard will have several other devices attached to it. Here is a summary of what I need to do:

Required:

• 2 RS232 serial ports (one used all the time for primary UI, the second one not continuous)
• 1 modem (9600+ baud ok) [Modem will be in simultaneous use with only one of the serial port devices, so interrupt sharing with one serial port is OK, but not both]
• Minimum permanent/long term storage: Whatever O/S requires + 1 MB (executable) + 512 KB (Data files)
• RAM: Minimal, whatever the O/S requires plus maybe 1MB for executable.

Nice to have:

• USB port(s)
• Ethernet network port
• Wireless network

Implementation languages (any O/S I will adapt to):

• First choice Java/C# (Mono ok)
• Second choice is C/Pascal
• Third is BASIC

Ok, given all this, I am having a lot of trouble finding hardware that will support this that is low in cost. Every manufacturer site I visit has a lot of options, and it's difficult to see if their offering will even satisfy my must-have requirements (for example they sometimes list 3 "serial ports", but it appears that only one of the three is RS232, for example, and don't mention what the other two are). The #1 constraint is cost, #2 is size.

Can anyone help me with this? This little task has left me thinking I should have gone for EE and not CS :-).

EDIT: A bit of background: This is a system currently in production, but the original programmer passed away, and the current hardware manufacturer cannot find hardware to run the (currently) DOS system, so I need to reimplement this in a modern platform. I can only change the programming and the motherboard hardware.