General Hardware Input/Output

Ports
Video, Keyboard, IDE(ATA), Parallel, Serial, USB, IR, RF, Joystick
Peripherals
Displays,LEDs, LCDs, Printers, Fax, Barcodes, Cameras, Speech, Servos, Motors, Steppers, Mouse, Autos, Relays & Solenoids, Robots, Sensors,
Networks OSI 3 - Network layer
TCP/IP (aka "The Internet"), Packet Radio, EDI, Telephone / pagers
Busses and Communication Standards - OSI 2 - Data Link layer
- I2C, SPI, USB, X10, iButton
- PSI, ISA, VME, AGP, etc...
Interfacing OSI 1 - Physical Layer

Also:

See also:

/techref/pcbixmax.htm Maximum interconnect options from minimum board space
DesignGroupLa of DAC refers to:
http://www.digac.com/iosource.htm
Modem features like AT command set, DTMF decode and Caller ID Ring detect and audio I/O for PIC
http://www.learn-c.com/ Control And Embedded Systems. Tutorials and a Low cost PC IO board design.
http://www.beyondlogic.org/ Craig Peacock's superb guide to all things serial and parallel.
http://margo.student.utwente.nl/stefan/ has info on various ports (parallel, serial, keyboard, etc.)
The comp.sys.ibm.pc.hardware.* FAQ (posted on news.answers and comp.sys.ibm.pc.hardware.misc, available via ftp from ftp://rtfm.mit.edu/pub/usenet/comp.sys.ibm.pc.hardware.misc) contains connector/bus pinouts and other useful information.
http://www.hut.fi/~then/electronics/computer.html#pchardware IBM, Technical Reference, Personal Computer AT, 1984
"The IBM Personal Computer, from the Inside Out" by Sargent and Shoemaker (published by Addison-Wesley) provides a lot of information about interfacing an IBM type PC to various things.
Talking to a floppy control from NC4000:
ftp://ftp.hal.com/pub/elvey/floppy.txt
Using a non-DOS machine to talk to a DOS disk
ftp://ftp.hal.com/pub/elvey/disk.txt
http://www-techdoc.intel.com and www.national.com Look up the datasheets for their super-IO parts, which have Paralell Port, Serial Port, RTC, Floppy Controller, all in one chip.
http://www.doc.ic.ac.uk/~ih/doc/adc_dac/
16- and 32-bit DLLs for port I/O may be found at: http://www.lvr.com
WINio.Dll and WIN32io for Windows 95 http://www.ping.be/~ping0751
Accessing PC I/O ports in Windows http://www.rain.org/~pra
EDE300 Application Note #1: Device Control via the PC http://www.elabinc.com In the 'Integrated Circuits' section under 'EDE300'
The Analog Devices AD9850 is a CMOS, 125 MHz complete direct digital synthesiser on a single chip. It uses a single 5 V or 3.3 V supply, and with a 125 MHz clock, can generate a low-distortion sine wave or a square wave, from under 1 Hz up to about 60 MHz, with a tuning resolution of 0.0291 Hz. Full data on the device is available from ADI's web site: http://www.analog.com
Commercial Communication Standards from the Defense Information Systems Agency
http://www.vex.net/~pcook/rec.audio.pro/ - audio recording info.

"low-cost interface boards" to plug into a PC (ISA, PCI, serial, parallel, USB, FireWire, ...)

analog input/output: see io/atod.htm
...
digital input/output
...

See:

Also see

Questions:

dude2z@yahoo.com asks:
I'm trying to build be a cnc machine controlled with a PC computer.

Has anybody used the X100 PC ISA I/O board from Tecel?

I would like to know how reliable is it.

Dod...
$40.00 : the X100 PC ISA I/O board from Tecel http://tecel.com/x100/

See:

/techref/io/mics.htm Microphones

Interested:

Maximum interconnect options from minimum board space

General Hardware Input/Output

Busses and Communication Standards - OSI 2 - Data Link layer

Interfacing OSI 1 - Physical Layer

Also: