Parallel Port Addresses vs. Modes
Parallel Port
Address
Parallel Port
Address
Parallel 1 Parallel 3
Compatible
03BC-03BF
Compatible 0278-027B
Enhanced
1278-127D
Enhanced 0278-027D
Extended
1278-127F
Extended 0278-027F
Parallel 2 Parallel 4
Compatible
0378-037B
Compatible 1378-137B
Enhanced
0378-037D
Enhanced 1378-137D
Extended
0378-037F
Extended 1378-137F

Notes:
   Many software drivers cannot handle addresses outside of 278-3BF. Parallel 4 (all modes) and the enhanced/extended Parallel 1 addresses are probably NOT supported unless you use OS/2 or a *nix. 
   Parallel 1 has a primary address of 3BC-3BF. IBM says that the DMA controller does NOT support that address, so that's where the odd 1278-127F come from.

Compatible is the old-styled unidirectional printer port
Enhanced is what?
Extended is bidirectional mode.
Enhanced/Extended ports use DMA. I don't know what the other difference is. Note that the enhanced port is one bit more than a standard port. Extended ports are two bits wider.

W95 Trivia
   I have installed an ECP Printer Port under "Add New Hardware". Go to the ECP Port's Resources and select the correct address and DMA Channel. It appears that DMA Channel 1 is used by DMA Arbitration Level 1. Am unsure if that's true, but it still works. I don't have a parallel port device yet to verify this other than my digital camera.
   I also hacked msports.inf in the [1aaa] section so that I had the extended port address. Dunno if that works better than the Compatible address, but it "looks" faster. Odd, but the IBM manual lists the enhanced mode, not the extended mode. The addresses in the adf for the planar are the ones ending with a "d". Does this mean compatible mode only? Or does it just show the non-DMA ports? Help!

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