fred smith wrote:
And some of t hose boards have a set of pins/header on the board and a little "slot fillter" thingy with a 9 pin serial socket on it and a small ribbon cable to plug into that header, which will then provide access to the second serial port. I've seen a lot of ASUS boards like that. wouldn't surpirse me if other vendors to it, too. probably saves board design complexity and maybe a few hundredths of a penny per board. :)
and, many of the -newest- boards have no serial (or parallel) at all, not even a header. COM ports are a legacy ISA device, and they are removing the ISA stub entirely (the other remaining use of which was the floppy controller, which also is left off these newest boards). when you get rid of this stuff, you get rid of the ancient 8257 ISA DMA controller emulation.
my newest PC build, I needed serial for a weather station, an older cell phone, and a older GPS... so rather than mess with USB serial dongles, I got a $17 4 port PCI-E serial controller, which actually looksl ike 16550 UARTs to the host. works great. was branded Sabrent, I think, that or Syba.